A tribunal heard how Rabbi Yitzhak Barda from Ramat Gan had taken part in a scam under which applicants wrote to another rabbi in France in order to receive a certificate stating they were Jewish.
Under Israeli law, any certified Jew is entitled to Israeli citizenship.
Barda was found guilty on Sunday and is to be sentenced at a later date.
The court rejected Barda's argument the money he received was to be used for "religious institutions". The sums involved were not known.