The agency, which employs 55 staff, will continue to be run as it was under McCann Erickson ownership. Jonathan Fine, who founded McCann Leeds in 1977 as The Fine Company, will remain as the chief executive of the agency.
Chris Lovell, the Golley Slater chief executive, said the deal would build on the strategic objectives for its business growth and add weight to its results-based marketing solutions offering.
"This is an area in which the McCann Erickson Leeds business excels and the reason we identified and bought the business," he said.
McCann Leeds was bought by McCann in 1999 and developed into an integrated communications business. Its clients include Procter & Gamble, Daihatsu, Lufthansa and the Carbon Trust.
Golley Slater bought the London digital agency Push Digital in February, the Edinburgh-based Talented in September 2005 and the Birmingham-based agency Mad Avenue in May last year.
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