Media group Emap has warned underlying revenues were being hit by difficult trading conditions.
The company said circulation had grown at weekly titles, such as Grazia, in its UK consumer magazine division but had declined for men's and car magazines.
Emap also owns a raft of radio stations - including Birmingham-based Kerrang! 105.2 - which had enjoyed a good start to the year in advertising.
However, chairman Adam Broadbent, who is stepping down, said: "Trading in the first two months of the financial year was in line with our expectations but the trends that are now emerging make us more cautious about the prospects for underlying revenue, which may be marginally down in the first half."
He said for the year as a whole underlying revenues are likely to be flat. Shares were down ten per cent following the announcement.
Last month, Emap sold its struggling French division to Arnoldo Mondadori Editore, the Italian publisher of glossy magazine Grazia, for £380 million.
Emap and Mondadori already had a relationship as Emap secured the licence to launch a UK version of Grazia, a title started by Mondadori in 1938 as Italy's first women's magazine.
The French operation was put up for sale in February, with the company later reporting a 25 per cent fall in annual profits for the division to £38 million. Underlying r evenues came in at £854 million for the year to March 31, while first half revenues hit £554 million in the six months to September 30 last year.
Analyst Charles Peacock, of Seymour Pierce stockbrokers, said: "The trading update indicates a deterioration in the outlook, leading it to expect an underlying decline in revenues in the first half and broadly flat revenues for the full year to March 2007.
"This compares with its previous guidance of underlying growth of around one per cent."
Despite the weaker outlook for its magazines, Mr Broad-bent said radio advertising had enjoyed a good year so far.
"Over the full year, we expect to continue to outper-form the UK radio market due to our strong local brands and national reach," he said.
The company also owns radio brands including Kiss, Magic and Heat.
Numis analyst Lorna Tilbian said: "Emap have issued a cautious AGM statement, highlighting the challenges facing UK consumer-facing media with respect to soft current trading and technology-driven structural change."
The company said its business-to-business unit was performing well with strong underlying growth, excluding public sector recruitment which has declined "more rapidly than expected".
Mr Broadbent is being succeeded by deputy chairman Alun Cathcart.