Scottish Radio Holdings (SRH) is to buy the Highland Radio group in Letterkenny, Co Donegal, for €7 million.
The amount paid will be made in cash drawn from SRH's existing banking facilities. SRH said it expects the purchase to enhance its earnings immediately.
The move will increase SRH's interests in the Irish radio market, where it already owns Today FM and FM 104.
The deal is conditional on the approval of the Competition Authority and the Minister for Enterprise, Trade and Employment.