The five-year senior credit agreement will allow revolver borrowings of up to $400 million.
The agreement also has an additional accordion feature to allow expansion by an additional $100 million.
Chairman and CEO Sudhakar Kesavan said the amendment is part of a company strategy to pursue acquisitions in the government and commercial markets.
The initial interest rate will be variable and equal to the London Interbank Offered Rate plus 150 basis points per annum.
The facility will also be subject to affirmative, negative and financial covenants.
RBS Citizens N.A. and PNC Capital Markets acted as joint lead arrangers and joint book runners.
Citizens Bank of Pennsylvania acted as administrative agent and lender and PNC Bank’s national association acted as syndication agent and lender.
ICF recently made a cash offer to acquire the GHK Holdings, a London-based consulting firm.
The company did not disclose a dollar amount and said it expected to close the deal by the end of the first quarter of fiscal year 2012.