FRS Digital will represent radio broadcasters using digital platforms including cable and satellite TV, DAB and online, and encourage a move towards this sector digital from radio advertisers.
The sales house plans to launch in the middle of the year.
Neil Webster, managing director of First Radio Sales, said: "FRS Digital will replicate what we do in our analogue business."
He added that the new digital arm will offer "an easy, accessible and effective way of reaching the growing audiences and advertising inventory these digital services offer. The initial reaction has been fantastic."
Figures from the Digital Radio Development Bureau and Dixons show digital radios are outselling analogue products by two to one.