Since Saatchi & Saatchi launched the first UK edition in 1972, advertising has largely consisted of press work and has been created in-house by publisher the National Magazine Company.
The search for an agency follows the appointment last December of branding consultancy Rise Communications, which was hired to create a strategy for the brand.
A spokeswoman for Natmags said: "We are talking to agencies as part of our larger strategy with Rise Communications." She added that a shortlist would be announced shortly.
It is understood that a number of agencies have been approached to pitch and that media, currently held by Initiative Media, will not be affected by the creative review.
The Cosmopolitan brand has suffered a knock of late, with handbag-sized rival Glamour overtaking it as the top seller in the UK. In the most recent set of ABC's, Cosmopolitan slipped back to 460,655, whilst Glamour stepped up to 582,690.
Jan Adcock, Cosmopolitan's publishing director, said recently that to beat Glamour, it would have to spend heavily on marketing and drop its cover price, which would dent its profitability.
"We have built solid, sustainable circulation and ad revenue and don't deliver our advertisers any less than before Glamour's launch," she said.
NatMags is currently piloting a smaller format in WH Smith's outlets in major railway stations and a national roll-out has been predicted for later this year.
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