The trial took place in Kurgan-Tyube, some 80 kilometers south of the capital, Dushanbe.
The judge said Russian Vladimir Sadovnichy and Estonian national Alexei Rudenko were sentenced to 10 1/2 years each but that the sentences were reduced under an amnesty.
Both men deny the charges.
They were detained after landing in Kurgan-Tyube in March with their two aircraft on a flight from Afghanistan, where they had been doing humanitarian work, bound for Russia.
Tajik authorities ordered them to return to Kabul, but the two pilots said they were forced to make an emergency landing for refueling. After a spare engine was found on one of the planes, the pilots were accused of smuggling and the two aircraft were seized.
The Russian Foreign Ministry responded to the verdict by saying it was too harsh and "politically charged," and warned it could harm Russian-Tajik relations.
with additional reporting by Russian news agencies
DUSHANBE -- A Tajik court has sentenced two pilots working for a Russian aviation company to 8 1/2 years in prison for border violations and smuggling, RFE/RL's Tajik Service reports.