<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>2103100 - Disclosure - New Accounting Pronouncements</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><CurrencyCode /><FootnoteIndexer /><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios><MCU><KeyName /><CurrencySymbol /><contextRef><ContextID>D2013Q2YTD</ContextID><EntitySchema>http://www.sec.gov/CIK</EntitySchema><EntityValue>0000764764</EntityValue><PeriodDisplayName /><PeriodType>duration</PeriodType><PeriodStartDate>2013-01-01T00:00:00</PeriodStartDate><PeriodEndDate>2013-06-30T00:00:00</PeriodEndDate><Segments /><Scenarios /></contextRef><UPS /><CurrencyCode /><OriginalCurrencyCode /></MCU><CurrencySymbol /><Labels><Label Key="CalendarSupplement" Id="0" Label="6 Months Ended" /><Label Key="Calendar" Id="1" Label="Jun. 30, 2013" /></Labels></Column></Columns><Rows><Row FlagID="0"><Id>1</Id><IsAbstractGroupTitle>true</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>1</Level><ElementName>us-gaap_NewAccountingPronouncementsAndChangesInAccountingPrinciplesAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>New Accounting Pronouncements and Changes in Accounting Principles [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_ScheduleOfNewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>terseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="D2013Q2YTD" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div style="font-family:Times New Roman;font-size:10pt;"&gt;&lt;div style="line-height:120%;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;New Accounting Pronouncements&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:36px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Disclosures about offsetting assets and liabilities &amp;#8211; &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In December 2011, the Financial Accounting Standards Board (FASB) issued accounting guidance on disclosures about offsetting assets and liabilities.  The guidance requires entities to disclose both gross and net information about instruments and transactions that are offset in the statement of financial position, as well as instruments and transactions that are subject to an enforceable master netting arrangement or similar agreement.  In January 2013, the FASB issued guidance clarifying the scope of the disclosures to apply only to derivatives, including bifurcated embedded derivatives, repurchase and reverse repurchase agreements and securities lending and securities borrowing transactions.  This guidance was effective January 1, 2013, with retrospective application required.  The guidance did not have a material impact on our financial statements.  See Note 5 for additional information.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Reporting of amounts reclassified out of accumulated other comprehensive income &amp;#8211; &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In February 2013, the FASB issued accounting guidance on the reporting of reclassifications out of accumulated other comprehensive income.  The guidance requires an entity to present, either on the face of the statement where net income is presented or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income if the amount is reclassified to net income in its entirety in the same reporting period.  For other amounts not required to be reclassified in their entirety to net income in the same reporting period, a cross reference to other disclosures that provide additional detail about the reclassification amounts is required.  This guidance was effective January 1, 2013 and did not have a material impact on our financial statements.  See Note 2 for additional information.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Joint and several liability arrangements &amp;#8211; &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In February 2013,&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt; &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;the FASB issued accounting guidance on the recognition, measurement and disclosure of obligations resulting from joint and several liability arrangements.  The guidance requires an entity to measure obligations resulting from joint and several liability arrangements for which the total amount of the obligation within the scope of this guidance is fixed at the reporting date, as the sum of the amount the reporting entity agreed to pay on the basis of its arrangement among its co-obligors and any additional amount the reporting entity expects to pay on behalf of its co-obligors.  The entity is also required to disclose the nature and amount of the obligation as well as any other information about those obligations.  This guidance is effective January 1, 2014, with retrospective application required.  We are currently reviewing the impact of this guidance on our financial statements and expect to complete this evaluation in 2013.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Parent's accounting for the cumulative translation adjustment upon derecognition of certain subsidiaries or groups of assets within a foreign entity or of an investment in a foreign entity &amp;#8211; &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In March 2013, the FASB issued accounting guidance on the parent's accounting for the cumulative translation adjustment (CTA) upon derecognition of certain subsidiaries or groups of assets within a foreign entity or of an investment in a foreign entity.  The new standard clarifies existing guidance regarding when the CTA should be released into earnings upon various deconsolidation and consolidation transactions.  This guidance is effective January 1, 2014.  We do not expect the adoption to have a material impact on our financial statements.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;text-align:justify;text-indent:30px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt; &amp;#8211; &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;July 2013, the FASB issued accounting guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. &amp;#160;The guidance requires an unrecognized tax benefit, or a portion of an unrecognized tax benefit, to be presented as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward in the financial statements if available under the applicable tax jurisdiction. &amp;#160; The guidance is effective January 1, 2014. &amp;#160;We do not expect the adoption to have a material impact on our financial statements.&lt;/font&gt;&lt;/div&gt;&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>Tabular disclosure of changes in accounting principles, including adoption of new accounting pronouncements, that describes the new methods, amount and effects on financial statement line items.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Statement of Financial Accounting Standard (FAS)

 -Number 154

 -Paragraph 2, 17, 18

 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 2: http://www.xbrl.org/2003/role/presentationRef

 -Publisher SEC

 -Name Regulation S-X (SX)

 -Number 210

 -Section 01

 -Paragraph b

 -Subparagraph 6

 -Article 10



Reference 3: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 270

 -SubTopic 10

 -Section 45

 -Paragraph 12

 -URI http://asc.fasb.org/extlink&amp;oid=6372559&amp;loc=d3e725-108305



Reference 4: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 270

 -SubTopic 10

 -Section 45

 -Paragraph 13

 -URI http://asc.fasb.org/extlink&amp;oid=6372559&amp;loc=d3e765-108305



Reference 5: http://www.xbrl.org/2003/role/presentationRef

 -Publisher AICPA

 -Name Accounting Principles Board Opinion (APB)

 -Number 28

 -Paragraph 23, 24

 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 6: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 250

 -SubTopic 10

 -Section 50

 -Paragraph 1

 -URI http://asc.fasb.org/extlink&amp;oid=6801783&amp;loc=d3e22499-107794



Reference 7: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 250

 -SubTopic 10

 -Section 50

 -Paragraph 2

 -URI http://asc.fasb.org/extlink&amp;oid=6801783&amp;loc=d3e22580-107794



Reference 8: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Glossary Accounting Change

 -URI http://asc.fasb.org/extlink&amp;oid=6503790



Reference 9: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Glossary Direct Effects of a Change in Accounting Principle

 -URI http://asc.fasb.org/extlink&amp;oid=6510796



Reference 10: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Glossary Indirect Effects of a Change in Accounting Principle

 -URI http://asc.fasb.org/extlink&amp;oid=6515603



Reference 11: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Glossary Change in Accounting Principle

 -URI http://asc.fasb.org/extlink&amp;oid=6507316



Reference 12: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 270

 -SubTopic 10

 -Section S99

 -Paragraph 1

 -Subparagraph (SX 210.10-01.(b)(6))

 -URI http://asc.fasb.org/extlink&amp;oid=6958853&amp;loc=d3e46468-122699



Reference 13: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Topic 250

 -SubTopic 10

 -Section 50

 -Paragraph 3

 -URI http://asc.fasb.org/extlink&amp;oid=6801783&amp;loc=d3e22583-107794



Reference 14: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

 -Glossary Retrospective Application

 -URI http://asc.fasb.org/extlink&amp;oid=6523989



</ElementReferences><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>New Accounting Pronouncements</Label></Row></Rows><Footnotes /><IsEquityReport>false</IsEquityReport><ReportName>New Accounting Pronouncements</ReportName><MonetaryRoundingLevel>UnKnown</MonetaryRoundingLevel><SharesRoundingLevel>UnKnown</SharesRoundingLevel><PerShareRoundingLevel>UnKnown</PerShareRoundingLevel><ExchangeRateRoundingLevel>UnKnown</ExchangeRateRoundingLevel><HasCustomUnits>true</HasCustomUnits><IsEmbedReport>false</IsEmbedReport><IsMultiCurrency>false</IsMultiCurrency><ReportType>Sheet</ReportType><RoleURI>http://finance.cat.com/role/NewAccountingPronouncements</RoleURI><NumberOfCols>1</NumberOfCols><NumberOfRows>2</NumberOfRows></InstanceReport>
