September 22, 2006

VIA FACSIMILE AND U.S. MAIL

Mr. Jay Webb
Review Accountant
Securities and Exchange Commission
Division of Corporate Finance
100 F Street, N. E.
Washington, DC 20549

Re:	Form 8-K filed July 26, 2006
	File No. 1-10317

Dear Mr. Webb:

We have included our response pursuant to telephonic communication on September 14, 2006. We have revised Exhibit A and the language below to include only Non-GAAP net income and Non-GAAP net income per basic and diluted share with the accompanying reconciliations for the periods presented.

Questions repeated and related responses to phone conversation:

General

Form 8-K filed July 26, 2006

1. Please refer to prior comment 3. As previously requested, please remove the “Non-GAAP Consolidated Statement of Operations” from your future filings. We believe your current disclosures still do not comply with Item 10 (e)(1)(i) of regulation S-K because for each non-GAAP measure presented on your “Non-GAAP Consolidated Statement of Operations”, you do not provide a numerical reconciliation for each non-GAAP measure to the most directly comparable GAAP financial measure. Also, you do not specifically disclose the following information for each non-GAAP measure presented on your “Non-GAAP Consolidated Statement of Operations”:

• the manner in which management uses the non-GAAP measure to conduct or evaluate its business;

• the material limitations associated with use of the non-GAAP financial measure as compared to the use of the most directly comparable GAAP financial measure;

Mr. Jay Webb
September 22, 2006
Page 2

• the manner in which management compensates for these limitations when using the non-GAAP financial measure; and

• the substantive reasons why management believes the non-GAAP financial measure provides useful information to investors.

Please remove the “Non-GAAP Consolidated Statements of Operations” from your future filings to include disclosures that comply with Item 10(e)(1)(i) of Regulation S-K. Please demonstrate in your response how you will address our concerns on these matters.

The Company proposes to include the below noted information under “For the 8-K filing” as requested in future filings. In addition, the Company has modified the “Non-GAAP Consolidated Statement of Operations” as the Staff requested.

For the 8-K filing:

Use of Non-GAAP Financial Information

LSI Logic has referenced non-GAAP financial information in the news release.

LSI Logic management believes that the presentation of non-GAAP net income and non-GAAP net income per basic and diluted share provides important supplemental information to management and investors regarding financial and business trends relating to the Company’s financial condition and results of operations. Management believes that the use of these non-GAAP financial measures provides consistency and comparability with our past financial reports.

Management has historically used these non-GAAP measures when evaluating operating performance because we believe that the inclusion or exclusion of the items described below provides an additional measure of our core operating results and facilitates comparisons of our core operating performance against prior periods and our business model objectives. We have chosen to provide this information to investors to enable them to perform additional analyses of past, present and future operating performance and as a supplemental means to evaluate our ongoing core operations. Externally, we believe that these non-GAAP measures continue to be useful to investors in their assessment of our operating performance and the valuation of our Company.

Internally, these non-GAAP measures are significant measures used by management for purposes of:

• evaluating the core operating performance of the Company;

• determination of bonus compensation for certain key employees;

• establishing internal budgets;

Mr. Jay Webb
September 22, 2006
Page 3

• calculating return on investment for development programs and growth initiatives;

• comparing performance with internal forecasts and targeted business models;

• strategic planning;

• evaluating and valuing potential acquisition candidates and how their operations compare to the Company’s operations; and

• benchmarking performance externally against our competitors.

Non-GAAP financial measures:

Non-GAAP net income:

Non-GAAP net income is important to the Company for the reasons noted above and excludes the following items:

• Stock-based compensation. Stock-based compensation relates primarily to stock awards such as options and restricted stock units that are issued by LSI Logic Corporation. Stock-based compensation is a non-cash expense that varies in amount from period to period and is dependent on market forces that are difficult to predict. As a result of this unpredictability, management excludes this item from its internal operating forecasts and models. Management believes that non-GAAP measures adjusted for stock-based compensation provide investors with a basis to measure the Company’s core performance against the performance of other companies without the variability created by stock-based compensation.

• Amortization of acquisition related intangibles and in-process research and development. These charges are acquisition-related charges. Amortization of acquisition-related intangibles relate to purchased technology in acquisitions such as existing technology, patents and trademarks. In-process research and development relates to projects in process as of the acquisition date that have not reached technological feasibility and are immediately expensed. These charges are not factored into management’s evaluation of potential acquisitions, or our performance after completion of acquisitions, because they are not related to our core operating performance, and the frequency and amount of such charges vary significantly based on the size and timing of our acquisitions and the maturities of the businesses being acquired. Excluding this data provides investors with a basis to compare the Company against the performance of other companies without this variability.

Mr. Jay Webb
September 22, 2006
Page 4

• Restructuring of operations and other items, net. This represents charges/losses and gains that are not directly related to the Company’s ongoing or core business results. Management regularly excludes such items from internal operating forecasts and models because it is not considered a core operating activity for the Company and because the frequency and variability in the nature of the charges can vary significantly from period to period. Excluding this data provides investors with a basis to compare our company against the performance of other companies without this variability.

• Other charges and gains. Other charges and gains consist of gains or losses on equity investments and certain non-operating gains and losses that occur on an infrequent basis and vary greatly in amount. We do not regularly trade public equity securities nor do we plan on these securities positions for funding of ongoing operations. Management excludes these items because they do not affect our core operations. Excluding this data provides investors with a basis to compare our company against the performance of other companies without this variability.

• Non-GAAP income tax expense/benefit. This line item represents the amount of tax expense or benefit that the Company would accrue if it used non-GAAP results instead of GAAP results in the calculation of its tax liability.

Non-GAAP net income per basic and dilutive share:

The calculation of non-GAAP net income excluding special items per dilutive share is adjusted in the numerator for all the items discussed above under net income excluding special items. In the denominator, the number of non-GAAP dilutive shares excludes the following item:

• The treasury stock method used to calculate weighted outstanding shares on a dilutive basis requires amounts related to compensation costs attributable to future services and not yet recognized in the financial statements to be treated as proceeds that are assumed to be used to repurchase shares. As a result, this reduces the total number of weighted average shares for purposes of calculating GAAP weighted average shares on a dilutive basis. LSI does not include the effects of these compensation costs in its non-GAAP net income excluding special items. Management believes these amounts should not be applied to the calculation of shares to be repurchased in the computation of non-GAAP net income per diluted share.

Some of the limitations in relying on non-GAAP financial measures are discussed below in relation to the items excluded from those non-GAAP measures.

Mr. Jay Webb
September 22, 2006
Page 5

• Stock-based compensation. LSI’s stock-based incentive plans are important components of our employee incentive compensation arrangements and are reflected in our GAAP results under Statement of Financial Accounting Standards No. 123 (revised 2004), Share-Based payment, commencing with the first quarter of 2006. They need to be considered for a complete view of the costs of our compensation arrangements.

• Amortization of acquisition-related intangibles. Acquisitions have been an important part of our business strategy and the corresponding acquisition-related charges reflect the costs of choosing acquisitions as a form of growth strategy.

• Restructuring of operations and other items, net. This item reflects charges for severance, exit costs associated with leased facilities, asset impairment charges and gains on sales of no longer strategic assets. While no longer strategic to the future of the Company, such items reflect the costs of decisions made as part of running a business and are critical to a complete view of our historical results.

• Other charges and gains. This items as discussed above should be included for a complete view of our historical performance even though they are not related to our core operations.

• Non-GAAP income tax expense/benefit. This line item represents the amount of tax expense or benefit that the Company would accrue if it used non-GAAP results instead of GAAP results in the calculation of its tax liability. The limitation in it is that it does not include the effect of all the items excluded from the Non-GAAP financial statements.

All supplemental non-GAAP financial measures should be read in conjunction with the comparable information presented in accordance with generally accepted accounting principles in the United States of America and the Company’s most recent annual report on Form 10-K for the fiscal year ended December 31, 2005.

The Company has attached a reconciliation of GAAP to non-GAAP financial measures used by management for the second quarter ended July 2, 2006 (Exhibit A) for purposes of this letter. We would include a page for each period presented.

You may contact me directly if you have any questions at (408) 433-8000.

Very truly yours,

/s/ Bryon Look

BRYON LOOK

Executive Vice President &

Chief Financial Officer

LSI LOGIC CORPORATION

Consolidated Condensed Statements of Operations (GAAP)
(In thousands, except per share amounts)
(Unaudited)
Exhibit A

	Three Months Ended									Six Months Ended
	July 2,			April 2,			July 3,			July 2,			July 3,
	2006			2006			2005			2006			2005
Revenues	$	489,635		$	475,884		$	481,292		$	965,519		$	931,299
Cost of revenues		277,970			269,870			269,531			547,840			529,271
Stock-based compensation expense*		2,458			1,525			164			3,983			325
Total cost of revenues		280,428			271,395			269,695			551,823			529,596
Gross profit		209,207			204,489			211,597			413,696			401,703
Research and development		95,719			97,752			99,659			193,471			198,896
Stock-based compensation expense*		4,643			4,522			570			9,165			1,405
Total research and development		100,362			102,274			100,229			202,636			200,301
Selling, general and administrative		58,439			63,094			59,872			121,533			118,012
Stock-based compensation expense*		6,197			5,784			438			11,981			897
Total selling, general and administrative		64,636			68,878			60,310			133,514			118,909
Restructuring of operations and other items, net		(21,648	)		5,650			7,156			(15,998	)		8,689
Amortization of acquisition related intangibles		10,801			11,216			17,613			22,017			35,226
Income from operations		55,056			16,471			26,289			71,527			38,578
Interest expense		(6,428	)		(6,330	)		(6,320	)		(12,758	)		(13,030	)
Interest income and other, net		10,319			9,527			11,543			19,846			16,933
Income before income taxes		58,947			19,668			31,512			78,615			42,481
Provision for income taxes		5,100			6,500			6,250			11,600			12,500
Net income	$	53,847		$	13,168		$	25,262		$	67,015		$	29,981
Income per share:
Basic	$	0.14		$	0.03		$	0.06		$	0.17		$	0.08
Diluted	$	0.13		$	0.03		$	0.06		$	0.17		$	0.08
Shares used in computing per share amounts:
Basic		397,790			394,851			389,088			396,312			388,371
Diluted		405,613			402,189			393,427			404,213			391,954

* The Company adopted the provisions of SFAS No. 123(R) “Share-Based Payment” on January 1, 2006, using the modified prospective transition method.

A reconciliation between net income on a GAAP basis and non-GAAP net income including items a)-h) is provided in the following table:

Reconciliation of GAAP to Non-GAAP net income:

	Three Months Ended									Six Months Ended
	July 2,			April 2,			July 3,			July 2,			July 3,
	2006			2006			2005			2006			2005
GAAP net income	$	53,847		$	13,168		$	25,262		$	67,015		$	29,981
Special items:
a) Stock-based compensation expense – Cost of revenues		2,458			1,525			164			3,983			325
b) Stock-based compensation expense – R&D		4,643			4,522			570			9,165			1,405
c) Stock-based compensation expense – SG&A		6,197			5,784			438			11,981			897
d) Amortization of acquisition related intangibles		10,801			11,216			17,613			22,017			35,226
e) Restructuring of operations and other items, net		(21,648	)		5,650			7,156			(15,998	)		8,689
f) Gain on sale of certain equity securities		—			(1,429	)		(2,358	)		(1,429	)		(2,358	)
g) Gain on repurchase of convertible Subordinated Notes		—			—			(4,123	)		—			(4,123	)
h) Income tax effect		453			(770	)		—			(317	)		—
Total special items		2,904			26,498			19,460			29,402			40,061
Non-GAAP net income	$	56,751		$	39,666		$	44,722		$	96,417		$	70,042
Non-GAAP income per share:
Basic	$	0.14		$	0.10		$	0.11		$	0.24		$	0.18
Diluted**	$	0.14		$	0.10		$	0.11		$	0.24		$	0.18
Shares used in computing Non-GAAP per share amounts:
Basic		397,790			394,851			389,088			396,312			388,371
Diluted		435,312			405,841			393,427			407,835			391,954

** In computing diluted earnings per share for the three month period ended July 2, 2006, net income was increased by $3,500 for interest, net of taxes, on the $350 million convertible notes considered dilutive common stock equivalents.

Reconciliation of shares used in the calculation of GAAP to Non-GAAP diluted net income per share:

	Three Months Ended						Six Months Ended
	July 2,		April 2,		July 3,		July 2,		July 3,
	2006		2006		2005		2006		2005
Diluted shares used in per-share calculation — GAAP		405,613		402,189		393,427		404,213		391,954
Effect of SFAS (R)		3,619		3,652		—		3,622		—
Effect of $350 million convertible notes considered dilutive**		26,080		—		—		—		—
Diluted shares used in per-share calculation — Non-GAAP		435,312		405,841		393,427		407,835		391,954