The court also ordered Khodorkovsky and his co-defendant, Platon Lebedev, to pay a total of more than $615 million in taxes and penalties.
The conviction and sentence came on the 12th day of the laborious verdict-reading process in the most closely watched case of post-Soviet Russia. Outside the courtroom, demonstrators chanted, "Shame! Shame!"
Khodorkovsky, 41, the former head of the Yukos oil company, looked straight ahead as the sentence was pronounced. Prosecutors had asked for the maximum 10 years.
In a statement read outside the court by defense attorney Anton Drel, Khodorkovsky said he would not harshly criticize the judge, noting "the pressure she has come under from the initiators of the case when preparing the verdict."