Rakhimov, 72, who has led the republic since 1993, was nominated for the post by President Vladimir Putin, who has the right to nominate candidates for regional leaders under a 2004 law that cancelled gubernatorial elections.
Rakhimov has come under criticism for his authoritarian style of leadership, and measures to curtail free speech in the region. In May, the editor of an independent newspaper and the leader of an opposition group were detained after speaking out against human rights abuses and calling for a new government.
Human rights groups had protested against widespread abuse in a brutal four-day police crackdown in the republic last December.
The Putin-proposed law on nominating candidates has been criticized by rights groups in Russia and abroad as undemocratic. More than 50% of members of the local legislature must approve the nominee for the candidate to become regional leader.
The Constitution prohibits more than two consecutives terms in office for federal and regional presidents, but the Constitutional Court ruled in 2002 that presidential terms before October 1999 do not count.
Rakhimov won the previous direct presidential campaign in 2003 although he was challenged by strong candidates, including Sergei Veremeyenko, a co-owner of Kremlin-connected Mezhprombank, and Ralif Safin, former vice president of LUKoil, Russia's largest independent oil producer.
Both companies have strong interests in the republic's major petrochemical facilities, which are controlled by the local administration.
Rakhimov's leadership campaign in December 2003 was marred by scandals, including the seizure by federal police of a batch of fake ballot papers from a publishing house controlled by the republic's administration, along with other violations.
