By David Willey
BBC News, Rome
Pope Benedict has given his blessing to taking adverts on Vatican Radio
Vatican Radio - the voice of the Roman Catholic church - is going commercial in July to meet rising costs.
It is one of the world's oldest broadcasters, first going on the air as long ago as 1931.
But the station now costs about $30m (21.4m euros, £18.8m) a year to run and the Vatican has been looking for ways of raising new funding.
An advertising agency is to vet the radio ads to make sure they are in keeping with moral standards.
Vatican Radio's first transmitter was designed by the Italian who carried out the world's first long distance voice transmission - Guglielmo Marconi.
The station, known as the Voice of the Pope, broadcasts worldwide by short, medium and long wave, by FM in Rome, and also on the internet.
On 6 July it will transmit its first commercial advert.
The Vatican has chosen the Italian electricity multinational ENEL as its first commercial radio sponsor.
But Vatican Radio hopes to attract other advertisers from around the world to help meet increasing costs.
An agency will filter all radio ads to make sure they are in keeping with the high moral standards of the Catholic Church, according to the official Vatican spokesman.
Pope Benedict XVI has personally approved Vatican Radio's new experimental commercial venture.