Russian President Vladimir Putin has signed a law ordering the country's first post-Soviet census to begin in October.
The census law was adopted in December by the lower house of Parliament, the State Duma, and approved by the upper house earlier this month.
The last census took place in 1989, two years before the collapse of the Soviet Union.
Russia's population has been falling steadily since the Soviet Union's demise and is estimated at about 145 million.