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  <rr:ExpenseExampleWithRedemptionTableTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;div style="display:none"&gt;~ http://www.iShares.com/role/ScheduleExpenseExampleTransposediSharesBarclaysGNMABondFund column period compact * ~&lt;/div&gt;</rr:ExpenseExampleWithRedemptionTableTextBlock>
  <dei:EntityRegistrantName contextRef="Duration_14Feb2011_13Feb2012">iSHARES TRUST</dei:EntityRegistrantName>
  <dei:EntityCentralIndexKey contextRef="Duration_14Feb2011_13Feb2012">0001100663</dei:EntityCentralIndexKey>
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  <rr:ObjectiveHeading contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Investment Objective &lt;/b&gt;</rr:ObjectiveHeading>
  <rr:ObjectivePrimaryTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">The iShares Barclays GNMA Bond Fund (the &amp;#8220;Fund&amp;#8221;) seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of the Barclays U.S. GNMA Bond Index (the &amp;#8220;Underlying Index&amp;#8221;).</rr:ObjectivePrimaryTextBlock>
  <rr:ExpenseHeading contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Fees and Expenses &lt;/b&gt;</rr:ExpenseHeading>
  <rr:ProspectusDate contextRef="Duration_14Feb2011_13Feb2012">2012-02-13</rr:ProspectusDate>
  <rr:RiskReturnHeading contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;iSHARES&lt;sup style="POSITION: relative; BOTTOM: 0.8ex; VERTICAL-ALIGN: baseline"&gt;&amp;#174;&lt;/sup&gt; BARCLAYS GNMA BOND FUND&lt;/b&gt;&lt;br/&gt;Ticker: GNMA&amp;nbsp;&amp;nbsp;&amp;nbsp;Stock Exchange: NASDAQ</rr:RiskReturnHeading>
  <rr:ExpenseNarrativeTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">The following table describes the fees and expenses that you will incur if you own shares of the Fund. The investment advisory agreement between iShares Trust (the &amp;#8220;Trust&amp;#8221;) and BlackRock Fund Advisors (&amp;#8220;BFA&amp;#8221;) (the &amp;#8220;Investment Advisory Agreement&amp;#8221;) provides that BFA will pay all operating expenses of the Fund, except interest expenses, taxes, brokerage expenses, future distribution fees or expenses, and extraordinary expenses. &amp;#8220;Acquired Fund Fees and Expenses&amp;#8221; reflects the Fund pro rata share of the fees and expenses incurred by investing in other investment companies. The impact of Acquired Fund Fees and Expenses will be included in the total returns of the Fund. Acquired Fund Fees and Expenses are not used to calculate the Fund&amp;#8217;s net asset value per share (&amp;#8220;NAV&amp;#8221;) and, once included, will not be included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund&amp;#8217;s prospectus (the &amp;#8220;Prospectus&amp;#8221;). BFA, the investment adviser to the Fund, has contractually agreed to waive its management fees in an amount equal to Acquired Fund Fees and Expenses attributable to the Fund&amp;#8217;s investment in other registered investment companies through December 31, 2015. The contractual waiver may be terminated prior to December 31, 2015 only upon written agreement of the Trust and BFA. BFA has contractually agreed to waive any additional portion of its management fees necessary to limit the Total Annual Fund Operating Expenses to 0.20% of average daily net assets through December 31, 2013. The contractual waiver may be terminated prior to December 31, 2013 only upon written agreement of the Trust and BFA.&lt;br/&gt;&lt;br/&gt;You may also incur usual and customary brokerage commissions when buying or selling shares of the Fund, which are not reflected in the example that follows:</rr:ExpenseNarrativeTextBlock>
  <rr:ExpenseExchangeTradedFundCommissions contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">You may also incur usual and customary brokerage commissions when buying or selling shares of the Fund, which are not reflected in the example that follows:</rr:ExpenseExchangeTradedFundCommissions>
  <rr:OperatingExpensesCaption contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">Annual Fund Operating Expenses&lt;br/&gt;(ongoing expenses that you pay each year as a&lt;br/&gt;percentage of the value of your investments)</rr:OperatingExpensesCaption>
  <rr:ManagementFeesOverAssets id="Item_2" decimals="4" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="pure">0.0025</rr:ManagementFeesOverAssets>
  <rr:DistributionAndService12b1FeesOverAssets id="Item_3" decimals="4" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="pure">0</rr:DistributionAndService12b1FeesOverAssets>
  <rr:OtherExpensesOverAssets id="Item_4" decimals="4" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="pure">0</rr:OtherExpensesOverAssets>
  <rr:AcquiredFundFeesAndExpensesOverAssets id="Item_5" decimals="4" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="pure">0.0007</rr:AcquiredFundFeesAndExpensesOverAssets>
  <rr:ExpensesOverAssets id="Item_6" decimals="4" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="pure">0.0032</rr:ExpensesOverAssets>
  <rr:FeeWaiverOrReimbursementOverAssets id="Item_7" decimals="4" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="pure">-0.0012</rr:FeeWaiverOrReimbursementOverAssets>
  <rr:NetExpensesOverAssets id="Item_8" decimals="4" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="pure">0.002</rr:NetExpensesOverAssets>
  <rr:ExpensesRestatedToReflectCurrent contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">The expense information in the table has been restated, as of the Fund&amp;#8217;s most recent fiscal year end, to reflect current fees.</rr:ExpensesRestatedToReflectCurrent>
  <rr:ExpenseExampleHeading contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Example. &lt;/b&gt;</rr:ExpenseExampleHeading>
  <rr:ExpenseExampleNarrativeTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">This Example is intended to help you compare the cost of owning shares of the Fund with the cost of investing in other funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Fund&amp;#8217;s operating expenses remain the same.&lt;br/&gt;&lt;br/&gt;Although your actual costs may be higher or lower, based on these assumptions, your costs would be:</rr:ExpenseExampleNarrativeTextBlock>
  <rr:ExpenseExampleYear01 decimals="INF" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="USD">20</rr:ExpenseExampleYear01>
  <rr:ExpenseExampleYear03 decimals="INF" contextRef="Duration_14Feb2011_13Feb2012S000035915_MemberC000110080_Member" unitRef="USD">75</rr:ExpenseExampleYear03>
  <rr:PortfolioTurnoverHeading contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Portfolio Turnover. &lt;/b&gt;</rr:PortfolioTurnoverHeading>
  <rr:PortfolioTurnoverTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or &amp;#8220;turns over&amp;#8221; its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the Example, affect the Fund&amp;#8217;s performance.</rr:PortfolioTurnoverTextBlock>
  <rr:StrategyHeading contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Principal Investment Strategies &lt;/b&gt;</rr:StrategyHeading>
  <rr:StrategyNarrativeTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">The Underlying Index is a market-capitalization weighted index that measures the performance of mortgage-backed pass-through securities issued by the Government National Mortgage Association (&amp;#8220;GNMA&amp;#8221;).&lt;br/&gt;&lt;br/&gt;The Underlying Index includes fixed-rate mortgage pass-through securities issued by GNMA that have 30- or 15-year maturities. All securities in the Underlying Index must have a weighted average maturity of at least one year and have $250 million or more of outstanding face value. The securities in the Underlying Index are updated on the last calendar day of each month.&lt;br/&gt;&lt;br/&gt;BFA uses a &amp;#8220;passive&amp;#8221; or indexing approach to try to achieve the Fund&amp;#8217;s investment objective. Unlike many investment companies, the Fund does not try to &amp;#8220;beat&amp;#8221; the index it tracks and does not seek temporary defensive positions when markets decline or appear overvalued. &lt;br/&gt;&lt;br/&gt;Indexing may eliminate the chance that the Fund will substantially outperform the Underlying Index but also may reduce some of the risks of active management, such as poor security selection. Indexing seeks to achieve lower costs and better after-tax performance by keeping portfolio turnover low in comparison to actively managed investment companies.&lt;br/&gt;&lt;br/&gt;BFA uses a representative sampling indexing strategy to manage the Fund. &amp;#8220;Representative sampling&amp;#8221; is an indexing strategy that involves investing in a representative sample of securities that collectively has an investment profile similar to the Underlying Index. The securities selected are expected to have, in the aggregate, investment characteristics (based on factors such as market capitalization and industry weightings), fundamental characteristics (such as return variability, duration, maturity or credit ratings and yield) and liquidity measures similar to those of the Underlying Index. The Fund may or may not hold all of the securities in the Underlying Index.&lt;br/&gt;&lt;br/&gt;The Fund generally invests at least 90% of its assets in the securities of the Underlying Index and in investments that provide substantially similar exposure to the securities in the Underlying Index. However, the Fund may at times invest up to 20% of its assets in cash and cash equivalents, including money market funds advised by BFA or its affiliates, as well as in mortgage-backed pass-through securities issued by GNMA and treasury bonds not included in the Underlying Index, but which BFA believes will help the Fund track the Underlying Index.&lt;br/&gt;&lt;br/&gt;Most transactions in mortgage pass-through securities occur through standardized contracts for future delivery in which the exact mortgage pools to be delivered are not specified until a few days prior to settlement (&amp;#8220;to-be-announced (TBA) transactions&amp;#8221;). The Fund may enter into such contracts for fixed-rate pass-through securities on a regular basis. The Fund, pending settlement of such contracts, will invest the relevant assets in liquid, short-term instruments, including shares of money market funds advised by BFA or its affiliates. The Fund will assume its pro rata share of the fees and expenses of any money market fund that it may invest in, in addition to the Fund&amp;#8217;s own fees and expenses. The Fund may also acquire interests in mortgage pools through means other than such standardized contracts for future delivery.&lt;br/&gt;&lt;br/&gt;The Fund&amp;#8217;s investments in mortgage pass-through securities (including transactions occurring through TBAs) will be limited to GNMA issuances.&lt;br/&gt;&lt;br/&gt;The Fund may lend securities representing up to one-third of the value of the Fund&amp;#8217;s total assets (including the value of the collateral received).&lt;br/&gt;&lt;br/&gt;The Underlying Index is sponsored by an organization (the &amp;#8220;Index Provider&amp;#8221;) that is independent of the Fund and BFA. The Index Provider determines the composition and relative weightings of the securities in the Underlying Index and publishes information regarding the market value of the Underlying Index. The Fund&amp;#8217;s Index Provider is Barclays Capital Inc. (&amp;#8220;Barclays Capital&amp;#8221;).&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Industry Concentration Policy. &lt;/b&gt;The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries, to approximately the same extent that the Underlying Index is concentrated. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions are not considered to be issued by members of any industry.</rr:StrategyNarrativeTextBlock>
  <rr:RiskHeading contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Summary of Principal Risks &lt;/b&gt;</rr:RiskHeading>
  <rr:RiskNarrativeTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">As with any investment, you could lose all or part of your investment in the Fund, and the Fund&amp;#8217;s performance could trail that of other investments. The Fund is subject to the principal risks noted below, any of which may adversely affect the Fund&amp;#8217;s NAV, trading price, yield, total return and ability to meet its investment objective.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Asset Class Risk.&lt;/b&gt; Securities in the Underlying Index or in the Fund&amp;#8217;s portfolio may underperform in comparison to the general securities markets or other asset classes.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Call Risk.&lt;/b&gt; During periods of falling interest rates, an issuer of a callable bond held by the Fund may &amp;#8220;call&amp;#8221; or repay the security before its stated maturity, and the Fund may have to reinvest the proceeds at lower interest rates, resulting in a decline in the Fund&amp;#8217;s income.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Concentration Risk. &lt;/b&gt;To the extent that the Fund&amp;#8217;s investments are concentrated in a particular region, market, industry or asset class, the Fund may be susceptible to loss due to adverse occurrences affecting that region, market, industry or asset class.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Credit Risk.&lt;/b&gt; The Fund is subject to the risk that debt issuers and other counterparties may not honor their obligations or may have their debt downgraded by ratings agencies.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;GNMA Mortgage-Backed Securities Risk. &lt;/b&gt;Mortgage-backed securities (&amp;#8220;MBS&amp;#8221;) represent interests in &amp;#8220;pools&amp;#8221; of mortgages and are subject to credit, interest rate, prepayment and extension risk. MBS react differently to changes in interest rates than other bonds and the prices of MBS may reflect adverse economic and market conditions. Small movements in interest rates (both increases and decreases) may quickly and significantly reduce the value of certain MBS. Default or bankruptcy of a counterparty to a TBA transaction would expose the Fund to possible loss.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;High Portfolio Turnover Risk. &lt;/b&gt;The Fund may engage in active and frequent trading of its portfolio securities. High portfolio turnover (more than 100%) may result in increased transaction costs to the Fund, including brokerage commissions, dealer mark-ups and other transaction costs on the sale of the securities and on reinvestment in other securities. The sale of Fund portfolio securities may result in the realization and/or distribution to shareholders of higher capital gains or losses as compared to a fund with less active trading policies. Given the frequency of sales, such gain or loss will likely be short-term capital gain or loss and, in the case of a gain, would increase an investor&amp;#8217;s tax liability unless shares are held through a tax-deferred or exempt vehicle. These effects of higher than normal portfolio turnover may adversely affect Fund performance. In addition, investment in mortgage dollar rolls and participation in TBA transactions may significantly increase the Fund&amp;#8217;s portfolio turnover rate.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Income Risk. &lt;/b&gt;The Fund&amp;#8217;s income may decline when interest rates fall. This decline can occur because the Fund must invest in lower-yielding bonds as bonds in its portfolio mature, bonds in the Underlying Index are substituted or the Fund otherwise needs to purchase additional bonds.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Interest Rate Risk.&lt;/b&gt; An increase in interest rates may cause the value of fixed-income securities held by the Fund to decline.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Issuer Risk.&lt;/b&gt; Fund performance depends on the performance of individual securities to which the Fund has exposure. Changes to the financial condition or credit rating of an issuer of those securities may cause the value of the securities to decline.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Liquidity Risk.&lt;/b&gt; Liquidity risk exists when particular investments are difficult to purchase or sell. This can reduce the Fund&amp;#8217;s returns because the Fund may be unable to transact at advantageous times or prices.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Management Risk.&lt;/b&gt; As the Fund may not fully replicate the Underlying Index, it is subject to the risk that BFA&amp;#8217;s investment management strategy may not produce the intended results.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Market Risk.&lt;/b&gt; The Fund could lose money over short periods due to short-term market movements and over longer periods during market downturns.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Market Trading Risk.&lt;/b&gt; The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares, losses from trading in secondary markets, periods of high volatility and disruption in the creation/redemption process of the Fund. ANY OF THESE FACTORS, AMONG OTHERS, MAY LEAD TO THE FUND&amp;#8217;S SHARES TRADING AT A PREMIUM OR DISCOUNT TO NAV.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Non-Diversification Risk.&lt;/b&gt; The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund&amp;#8217;s performance may depend on the performance of a small number of issuers.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Passive Investment Risk.&lt;/b&gt; The Fund is not actively managed and BFA does not attempt to take defensive positions under any market conditions, including declining markets.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Securities Lending Risk. &lt;/b&gt;The Fund may engage in securities lending. Securities lending involves the risk that the Fund may lose money because the borrower of the Fund&amp;#8217;s loaned securities fails to return the securities in a timely manner or at all. The Fund could also lose money in the event of a decline in the value of the collateral provided for loaned securities or a decline in the value of any investments made with cash collateral. These events could also trigger adverse tax consequences for the Fund.&lt;br/&gt;&lt;br/&gt;&lt;b&gt;Tracking Error Risk.&lt;/b&gt; The performance of the Fund may diverge from that of the Underlying Index. Because the Fund employs a representative sampling strategy, the Fund may experience tracking error to a greater extent than a fund that seeks to replicate an index.</rr:RiskNarrativeTextBlock>
  <rr:RiskLoseMoney contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">As with any investment, you could lose all or part of your investment in the Fund, and the Fund&amp;#8217;s performance could trail that of other investments.</rr:RiskLoseMoney>
  <rr:RiskNondiversifiedStatus contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Non-Diversification Risk.&lt;/b&gt; The Fund may invest a large percentage of its assets in securities issued by or representing a small number of issuers. As a result, the Fund&amp;#8217;s performance may depend on the performance of a small number of issuers.</rr:RiskNondiversifiedStatus>
  <rr:BarChartAndPerformanceTableHeading contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Performance Information &lt;/b&gt;</rr:BarChartAndPerformanceTableHeading>
  <rr:PerformanceNarrativeTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">As of the date of the Fund&amp;#8217;s prospectus (the &amp;#8220;Prospectus&amp;#8221;), the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.</rr:PerformanceNarrativeTextBlock>
  <rr:PerformanceOneYearOrLess contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">As of the date of the Fund&amp;#8217;s prospectus (the &amp;#8220;Prospectus&amp;#8221;), the Fund has been in operation for less than one full calendar year and therefore does not report its performance information.</rr:PerformanceOneYearOrLess>
  <rr:FeeWaiverOrReimbursementOverAssetsDateOfTermination contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">December 31, 2013</rr:FeeWaiverOrReimbursementOverAssetsDateOfTermination>
  <rr:ExpensesNotCorrelatedToRatioDueToAcquiredFundFees contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">Acquired Fund Fees and Expenses are not used to calculate the Fund&amp;#8217;s net asset value per share (&amp;#8220;NAV&amp;#8221;) and, once included, will not be included in the calculation of the ratio of expenses to average net assets shown in the Financial Highlights section of the Fund&amp;#8217;s prospectus (the &amp;#8220;Prospectus&amp;#8221;).</rr:ExpensesNotCorrelatedToRatioDueToAcquiredFundFees>
  <rr:StrategyPortfolioConcentration contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;b&gt;Industry Concentration Policy. &lt;/b&gt;The Fund will concentrate its investments (i.e., hold 25% or more of its total assets) in a particular industry or group of industries, to approximately the same extent that the Underlying Index is concentrated. For purposes of this limitation, securities of the U.S. government (including its agencies and instrumentalities), repurchase agreements collateralized by U.S. government securities, and securities of state or municipal governments and their political subdivisions are not considered to be issued by members of any industry.</rr:StrategyPortfolioConcentration>
  <rr:AnnualFundOperatingExpensesTableTextBlock contextRef="Duration_14Feb2011_13Feb2012S000035915_Member">&lt;div style="display:none"&gt;~ http://www.iShares.com/role/ScheduleAnnualFundOperatingExpensesTransposediSharesBarclaysGNMABondFund column period compact * ~&lt;/div&gt;

</rr:AnnualFundOperatingExpensesTableTextBlock>
  <link:footnoteLink xlink:type="extended" xlink:role="http://www.xbrl.org/2003/role/link">
    <link:loc xlink:type="locator" xlink:href="#Item_2" xlink:label="ManagementFeesOverAssets" />
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