Three were sentenced to two to three years in a labor camp. The other five were sentenced to milder corrective labor measures and released.
All eight had pleaded not guilty and said they had been tortured while in custody.
Andrea Berg, who attended the trial on behal of the international watchdog group Human Rights Watch, said the judge dismissed the men's claims of maltreatment as an attempt to avoid responsibility "for their illegal activities."
The eight men say they will appeal the verdict.
The men were arrested in December on charges of Wahabbism and membership of Hizb ut-Tahrir, a banned religious group.
Human rights activists say the eight are among many arrested in recent months on suspicion of ties with a dissident imam, Obidkhon Qori Nazarov. Nazarov has been in hiding since 1998 after Tashkent authorities accused him of religious extremism and terrorism.
Last month, he was given political asylum in Europe after he asked the UN refugee agency for help.