Judges at the criminal appeals court in Athens have found former Defense Minister Akis Tsochatzopoulos guilty of money laundering. His sentence is due to be announced on Tuesday.
The charges relate to bribes that Tsochatzopoulos accepted in return for agreeing defense contracts between 1997 and 2001.
The court handed down guilty verdicts for 17 of the 19 suspects on trial after deeming they had cooperated with Tsochatzopoulos to launder the bribes through a network of offshore companies and property purchases.
His wife Viki Stamati, daughter Areti Tsochatzopoulou and cousin Nikos Zigras were among those convicted.
Judges acquitted businessman Pantelis Zachariadis and Cypriot lawyer Spyros Hatzinikolaou.
Tsochatzopoulos's trial lasted for five months, during which he denied the charges against him. The guilty verdict means he faces a jail term of between 10 and 20 years.