The ruling by an Istanbul court said Saran and his brother, Kenan Saran, were sentenced to two years and six months in jail for "inciting individuals to engage in illegal betting through advertising or various other means".
Sadettin Saran had denied any wrongdoing in his court defence, local media reported.
Saran was briefly detained by authorities earlier this year as part of a wide probe into drug use among Turkish celebrities, but was later released. He later announced that he would step down from his position, and the club in March announced it would hold an extraordinary congress on June 6th to 7th.
Authorities in Turkey have conducted wide-ranging investigations into alleged match-fixing and illegal betting in the country's professional football leagues.
Dozens of referees were suspended by the Turkish Football Federation, while several commentators, officials, and players, including those from top-tier clubs, were detained or arrested as part of the probe.
Fenerbahce's former chairman, Aziz Yildirim, has announced his candidacy to run the club. He will run against businessman Hakan Safi, as the Istanbul club seeks to end its 13-year championship drought. Saran is not running.