The group, which owns the Capital FM and Xfm radio stations in London, said radio revenues in the third quarter were down 16% and that overall revenues were down 6% for the year.
Capital, the UK's largest radio group, said revenues for October and November were likely to be down by around 7% on last year. It said it could not predict revenues for the last month of the year.
David Mansfield, chief executive of Capital, said, "We are unable to forecast with any degree of accuracy for December and beyond."
However, Mansfield delivered an upbeat message and said Capital was confident of the long-term prospects for radio advertising, and would continue to look for ways to expand its national radio presence.
Capital said revenues from continuing operations fell 1% to £123.2m. Capital paid a final dividend of 12.5p a share, making the total dividend unchanged at 18.5p.
Capital also announced that deputy chairman Peter Cawdron would move up to become chairman in January, taking over from the outgoing Ian Irvine, who is retiring.
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