The £20 million-billing shop, which will close in April, is currently discussing new agency arrangements with its clients while finding jobs for its dozen staff.
Mitchell Patterson's portfolio includes Patak's spices, Sacla pasta sauces, Royal Caribbean cruises, Cornhill Direct and the Danepak and Tulip bacon brands.
The agency has never had an overdraft and always been in profit. But Andrew Mitchell, its chairman and managing partner, admitted: "We don't like what we see ahead. There's just too much and better competition. Mother and Clemmow Hornby Inge are the new kids on the block and it's their turn now."
A fanfare of publicity accompanied the launch of the then Mitchell Patterson Aldred Mitchell in March 1990 by Neil Patterson, then Young & Rubicam's creative director, Mitchell, the vice-chairman of Publicis, and two other senior Publicis executives.
The founders expected their pedigree and experience would give them a head start. Although the agency performed solidly, it never achieved the profile of some of its contemporaries.
Since then, it has suffered from a depressed new-business environment, pressure on margins and the fuller range of advertising services now being provided by direct marketing, PR specialists and even media independents.
At the same time, the partners say their focus on so-called challenger brands has been thwarted by the communications supergroups which have become much better at servicing such business.