During the genocide, Mategeko was a priest in Hanika, in south-western Rwanda.
The clergyman appeared before the semi-traditional Gacaca Court of Gihundwe, also in south-western Rwanda.
He was sentenced for incitement to commit the massacres of Tutsis who had taken refuge in the Parish of Shangi, in the former prefecture of Cyangugu, south-western Rwanda, the radio station added.
The priest has maintained his innocence and announced that he was going to appeal.
Priest Mategeko was on trial alongside the former sub-prefect Theodore Munyangabe and the magistrate Jean Bimenyimana, who were also sentenced to life in prison in isolation.
The Gacaca courts are not presided by professional judges by people considered of high esteem in the society.
They can deliver sentences of up to life in prison in isolation, the maximum sentence in Rwanda, after the abolition of capital punishment in 2007.
© Hirondelle News Agency