The value of the deal was not disclosed, but it reportedly could be worth more than £20m.
Co-founders Miro Walker and Stuart Dean are set for a windfall following the deal with WPP Digital. Each founder owned 37 per cent of Cognifide prior to the deal.
Cognifide has 200 staff and annual revenues of £8.8m last year.
WPP also announced that its Chinese company JWT has also agreed to acquire Shanghai Egift Design and Production, a gift specialist firm in China.