Issuer Free Writing Prospectus
Dated May 11, 2009
Filed Pursuant to Rule 433
Registration Statement No. 333-137246
Berkshire Hills Bancorp, Inc. (the "Issuer"), has filed a registration statement (including a prospectus and a related prospectus supplement) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus and the prospectus supplement in that registration statement and other documents the Issuer has filed with the SEC for more complete information about the Issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov. Alternatively, the Issuer or the underwriters participating in the offering will arrange to send you the prospectus and the prospectus supplement if you request it by calling toll-free (866) 805-4128.

This presentation contains forward-looking statements (within the meaning of the Private Securities Litigation Reform Act of 1995) which involve significant risks and uncertainties. Actual results may differ materially from the results discussed in these forward-looking statements, including factors discussed in "Forward-Looking Statements" in the Company's 2008 Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, which are available at the Securities and Exchange Commission's internet website (www.sec.gov) and to which reference is hereby made. Except as required by law, the Company assumes no obligation to update any forward-looking statements, and undue reliance should not be placed on these statements. Forward Looking Statements Follow-on Common Stock Offering May 11, 2009

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Statements in the presentation regarding Berkshire Hills Bancorp that are not historical facts are "forward-looking statements". These statements reflect management's views of future events, and involve risks and uncertainties. For a discussion of factors that could cause actual results to differ materially from expectations, see "Forward Looking Statements" in the Prospectus Supplement and the Company's 2008 Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, which are available at the Securities and Exchange Commission's Internet website (www.sec.gov) and to which reference is hereby made. Actual future results may differ significantly from results discussed in these forward- looking statements, and undue reliance should not be placed on such statements. Except as required by law, the Company assumes no obligation to update any forward-looking statements. Safe Harbor Statement

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P.O. Box 1308, Pittsfield, MA 01202 — Executive Offices — 66 West Street, Pittsfield, MA 01201 Follow-on Common Stock Offering May 11, 2009 Michael P. Daly President & Chief Executive Officer Kevin P. Riley EVP & Chief Financial Officer Shepard D. Rainie EVP & Chief Risk Officer

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Offering Terms Issuer: Berkshire Hills Bancorp, Inc. (NASDAQ: BHLB) Type of Security: Follow-on Public Common Stock Offering Transaction Size: Approximately $30 million Over-Allotment Option: 15% Expected Pricing Date: May 11, 2009 Use of Proceeds: General corporate purposes, which may include, among other things, support for organic and opportunistic acquisition-based growth Lead Book-Running Manager: Sandler O'Neill + Partners, L.P. Co-Manager: Keefe, Bruyette & Woods

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Capital Raising Rationale Increase Berkshire Hill's ability to be opportunistic in a unique market environment Position the company to increase its tangible common equity / tangible assets ratio. TARP repayment anticipated from existing cash balances. Position the company for opportunities to increase market share across all business lines over the next 12-24 months Support overall organic growth across integrated business lines in existing regions The company assesses and analyzes the relative merits of acquisitions as part of its general strategy As these opportunities present themselves in the coming periods, this capital will keep the company well-positioned to act where economically viable and in the best interest of BHLB shareholders

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Our Growing Regional Franchise $2.7 billion in assets as of March 31, 2009 48 financial centers Three-state franchise Massachusetts, New York and Vermont Largest locally headquartered regional financial services company in primary market $640 million in managed assets - wealth management and investments Insurance agency with 100 professionals Strong growth from organic, de novo and acquisition strategies Distinctive culture as America's Most Exciting Bank SM

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Experienced Leadership Team Michael P. Daly President and CEO Kevin Riley EVP, CFO Sean Gray SVP, Retail Banking Background Bank of America Consumer Market Executive Background TD Banknorth Co-Regional Executive Background Bank of America Managing Director Background KeyBank EVP CFO Lawrence A. Bossidy Chairman David Farrell EVP, Integrated Services Background TJX Companies CVS / Caremark Division President Michael Oleksak EVP, Commercial Banking Shepard Rainie EVP, Risk Management

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Investment Opportunity Experienced and proven management team Diverse revenue sources Performance driven Differentiated brand and culture Leader in core markets Opportunity for growth in existing and new markets Disciplined risk management culture

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Positioned to Increase Market Share Note: The Company has a pending agreement to acquire CNB Financial Corp. in Worcester, Massachusetts, parent of Commonwealth National Bank. Commonwealth has six branches and had $197 million in deposits as of June 30, 2008. It was ranked 19th in Worcester County, with a 2.2% market share. Data as of June 30, 2008; Branch count is current Source: SNL Financial; FDIC Market Deposits Share Region ($mm) (%) Branches Rank Berkshire County 881 30.7 12 1 Pioneer Valley (Springfield) 513 4.4 10 11 Southern Vermont 277 6.3 7 5 New York Capital Region (Albany) 153 0.7 10 19

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Record Net Revenues and Earnings per Share in 2008 Net revenue growth from acquisitions and organic growth Improved net interest margin and efficiency ratio in 2008 Net Revenue Per Share - Diluted Diluted Earnings per Share $8.28 $9.45 $9.95 $2.00 $4.00 $6.00 $8.00 $10.00 2006 2007 2008 $1.29 $1.44 $2.06 $0.50 $0.75 $1.00 $1.25 $1.50 $1.75 $2.00 2006 2007 2008

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Solid 2008 Results Performance Measure BHLB Industry Change in core EPS (year-over-year) 8.4% (12.9%) Return on average assets 0.87% 0.50% Return on average total equity 6.5% 4.2% Core Return on average tangible common equity 16.2% 5.7% Net interest margin 3.44% 3.44% Fee income / total net revenue 28.3% 10.2% Efficiency ratio 61.4% 66.0% Net loan charge-offs / average total loans 0.19% 0.37% Non-performing assets / total assets at 12/31/08 0.48% 1.37% Meeting or beating industry performance on all measures Note: Industry data is based on median SNL data for exchange traded banks and thrifts for institutions with FYE 2008 data in the SNL database as of 2/3/09.

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Overview of 1st Quarter 2009 Results Earnings per share of $0.27 Net interest margin of 3.11% Record levels of deposits, growing 6% in Q1 as customers sought safety in Berkshire's 100% insured deposit accounts Fee income of $8.4 million or 32% of total net revenues Nonperforming assets decreased to 0.47% of total assets from 0.48% at December 31, 2008 Tangible common equity to tangible assets of 7.8%

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Recent Announcements Agreement to acquire CNB Financial, parent of $300 million Commonwealth National Bank with six branches in the Worcester, Mass. market Recruitment of New York commercial lending team Appointment of David Farrell as EVP, Integrated Services - Insurance and Wealth Management Application filed with regulators for repayment of TARP preferred stock

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Strong Capital Ratios Assumes 1,244,297 shares with a gross offering price of $24.11 based on Berkshire Hills' closing stock price on May 8, 2009, adjusted 7% for fees and expenses to a net price of $22.42 As of March 31, 2009 Tangible Common Equity / Tangible Assets 7.75% Proforma With Stock Offering (1) 8.75% Tangible Common Book Value Per Share $16.03 Proforma With Stock Offering $16.62 Total Equity / Total Assets 15.15% Proforma With Stock Offering 16.01% Common Book Value Per Share $30.54 Proforma With Stock Offering $29.80 Berkshire Bank Total Risk-Based Capital Ratio 12.2%

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Solid Loan Performance Note: Delinquent loans include all accruing loans delinquent 30 days or more. Charge-offs are based on quarterly net charge-offs, annualized. 0.00% 0.50% 1.00% 1.50% 2.00% Q107 Q207 Q307 Q407 Q108 Q208 Q308 Q408 Q109 Non-performing Assets / Assets Delinquent Loans / Loans Net Charge Offs / Loans

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Low Net Charge-Offs Annualized Net Charge First Quarter 2009 Quarter End Offs / Avg. Loans (Dollar Values in Thousands) Loan Balance (%) Residential $651,507 0.07% Home Equity and second mortgages 217,313 0.08% Auto & Other Consumer 123,430 1.84% Commercial Business 179,765 0.35% Commercial Real Estate- Other 665,001 0.38% Commercial Construction 132,362 2.45% Total $1,969,378 0.51%

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Loan Mix Managed for Quality Growth 7% organic growth in 2008 Indirect lending running off at 53% annual rate - 1st quarter 2009 Strong credit disciplines - no high LTV or sub-prime or Alt A loan programs All lending is to relationships in Berkshire's New England and New York lending areas 2005 2006 2007 2008 1Q09 Commercial Mtg 410.7 566.4 704.8 808 797 C&I 158.7 190.5 203.6 176 180 Residential 549.8 599.2 657 677 651 Consumer 301 342.9 378.6 346 341 Note: 2008 organic growth excludes indirect auto loans which are in run-off. $1,969 $2,007 $1,944 $1,699

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Diversified Commercial Loan Industry Exposure No loans to out of area relationships TOTAL COMMERCIAL LOANS = $977 MILLION As of March 31, 2009 Misc. Commercial 9% Other Services 11% Human Services 8% Apartments 8% Other CRE 8% Retailers 10% RE Development 9% Lodging 14% CRE Rental 23%

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Modest and Diversified Commercial Construction Portfolio TOTAL $132 MILLION = 7% OF TOTAL LOANS As of March 31, 2009 RESIDENTIAL C&D: $82 MILLION OTHER C&D: $50 MILLION Single Home Const. 5% Subdiv. Single Fam 16% Subdiv. Condo 25% Retail 10% Land Improved 3% Land Unimproved 8% Office 10% Other 6% Hotel 12% Multifamily 5%

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Overview of Acquisition of CNB Financial Purchase Price: $8.91 per share; $20.3 million in aggregate(1) Exchange Ratio: Fixed at 0.3696 Berkshire Hills shares per CNB share(2) Consideration: 100% stock Due Diligence: Completed comprehensive due diligence, including detailed review of loan and securities portfolio Expected Closing: Early Third Quarter of 2009 Transaction Structure: Tax-free exchange Conditions to Closing: Approval of CNB's shareholders and customary regulatory approval Transaction Multiple: Offer Price / Tangible Book Value: 104%(3) Expected Accretion / Dilution: Accretive to earnings per share in 2010 by $0.10(4) Dilutive to tangible book value per share $0.24 in 2009 closing adjustments and the net impact of transaction expenses on net income(5) Based on a Berkshire Hills stock price of $24.11 as of May 8, 2009 CFNA has 2,283,208 common shares outstanding as of April 2, 2009; BHLB will issue to CFNA shareholders approximately 843,874 shares of BHLB common stock Based on CFNA's tangible book value per share of $8.56 at December 31, 2008 2010 EPS accretion includes the effect of approximately 25% in pro forma non-interest expense cost savings Pro forma tangible book value includes the effect of an approximate $14 million pre-tax credit mark on CFNA's loan portfolio

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Transaction Highlights and Rationale Through the acquisition of CNB Financial, Berkshire Hills will gain a meaningful presence in the Worcester market Second largest city in New England(1) Contiguous to Berkshire Hills' existing markets of operation, making this a logical market expansion and facilitating ease of management and oversight The only Massachusetts-based regional bank that will be operating in the Worcester market Presents opportunity for significant upside CNB's commercial lending capabilities, combined with the size and strength of Berkshire Hills' balance sheet create ability to generate attractive incremental loan growth Ability to significantly enhance current retail platform as well as sell from Berkshire Hills' existing product base, such as wealth management and insurance Relative size of the transaction enables Berkshire Hills to fully grasp any associated risks and manage them effectively (1) By population; Based on U.S. Census Bureau Data

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Overview of CNB Financial Corp. Map excludes the Berkshire Hills branch at 212 Main Street in Oriskany Falls, New York. Map includes offices of Berkshire Insurance Group Date of CNB Financial's bank subsidiary's founding CNB 2008 Financial Highlights: Total Assets: $295 million Gross Loans: $242 million Total Deposits: $197 million Branches: 6 Date Founded: 2001(2) Berkshire Hills' Expanded Branch Network(1) Berkshire Hills Joins the Worcester Market Boston Worcester Springfield Albany

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CNB Financial's Loan Portfolio Low historic charge-off rate NPAs / Assets of 1.45% at December 31, 2008 Net charge-offs of 0.58% of average loans in 2008 (Dollar Values in Millions) December 31, 2008 Percent of Total Commercial and Industrial $53 22% Construction Loans $30 12% Other Commercial Real Estate $122 51% Residential Real Estate $24 10% Consumer $13 5% Total Loans $242 100% Loan Loss Allowance ($3) Net Loans $239

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Key Financial Estimates In the course of its due diligence, Berkshire Hills along with third-party advisors performed a comprehensive review of CNB's loan portfolio in order to understand and effectively account for any potential losses associated with the portfolio Expected credit mark amounts to approximately $14 million, of which $3 million is accounted for in CNB's loan loss reserve Based on an in-depth analysis of the resources needed to effectively manage and successfully operate CNB's franchise on a combined basis, Berkshire Hills' expects to realize cost savings of approximately 25% of CNB's operating expenses (approximately $2.3 million based on 2008 financials) Expected transaction costs of $4.5 million

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Attractive Stock Metrics Compared to Peers Pricing data as of May 8, 2009 Source: SNL Financial Price / Loans LTM Price TBV EPS Company City, State Ticker ($) (%) (x) Independent Bank Corp. Rockland, MA INDB 21.74 235 15.5 Washington Trust Bancorp, Inc. Westerly, RI WASH 18.49 173 13.9 First Niagara Financial Group, Inc. Lockport, NY FNFG 13.21 253 17.2 NBT Bancorp Inc. Norwich, NY NBTB 25.11 269 14.3 Community Bank System, Inc. De Witt, NY CBU 18.00 267 12.5 Tompkins Financial Corporation Ithaca, NY INDB 49.48 267 16.1 MEDIAN 267 15.2 Berkshire Hills Bancorp, Inc. Pittsfield, MA BHLB 24.11 150 13.6

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Why Invest in Berkshire Hills? Strong and experienced management team Strong credit culture and risk management profile Strategy to be a regional consolidator, growing and diversifying our financial services offerings and gaining a leading share in attractive northeastern markets Above average long term growth in loans, deposits and fee income Focus on earnings and performance Distinctive culture and core values Stock valuation metrics are attractive for shareholder returns