Kenya has published new broadcast regulations, which will place strict limits on sexual content and ban preachers from soliciting money on air.
Explicit content will only be allowed on the airwaves between 22:00 and 05:00 in order to protect children, Kenya's Communications Authority says.
Broadcasters have until June to comply with the new rules.
A BBC correspondent says this is the first time a concerted effort has been made to censor Kenyan radio stations.
The new rules apply to programmes as well as advertisements, programme listings and promotions.
Analysis: Anne Soy, BBC News, Nairobi
Popular radio stations in the country often broadcast explicit content during peak hours to attract audiences.
A morning ride to work on a bus in Kenya will often mean listening to radio call-ins from fathers confessing to having sexual feelings for their children, or women who are dissatisfied with the performance of their husbands in the bedroom.
Many listeners say they are happy that the authorities are now taking steps to censor inappropriate material.
The new broadcast code also bans preachers from soliciting money from audiences in exchange for blessings.
Some preachers are thought to have built large fortunes from the practice, gaining huge popularity in a country where 84% of the population are Christians, although there have been cases of people suing them when their blessings failed to materialise.
Traditional churches have been highly critical of these types of preachers, describing them as false teachers.