The sentence was given to Dmitry Pavlyuchenkov, who was convicted of assisting a criminal group by helping track down Politkovskaya in Moscow, RIA Novosti reported.
Pavlyuchenkov also supplied the killers with a gun, investigators said.
Politkovskaya, who worked for the left-leaning newspaper Novaya Gazeta, was shot in the elevator of her apartment building Oct. 7, 2006.
Her work had often included reports that were critical of the government's policies in North Caucasus and the leadership in Chechnya.
Pavlyuchenkov agreed to testify against five other suspects in the case: Lom-Ali Gaitukayev, the alleged mastermind of the killing; brothers Rustam, Ibragim and Dzhabrail Makhmudov; and Sergei Khadzhikurbanov, also formerly with the police. All are in custody and will be tried separately, officials said.
Rustam Makhmudov is accused of firing the gun that killed the journalist.
Pavlyuchenkov was also ordered to pay $98,000 to Politkovskaya's children, Ilya and Vera, who sued him for about $325,000, the Russian Legal Information Agency reported.