Visitors to the site see a black line across the site's logo and a message explaining the move.
The government says it wants greater powers to block sites that show child pornography, promote teenage suicide, and spread information about drugs.
But Wikipedia likens the proposed law to the Great Firewall of China.
Internet users and human rights activists have both argued that the scope of the law would be too wide, allowing officials to select "subjectively" which sites to blacklist.
The government is seeking to make amendments to its Act for Information, which is due for review in the Duma, Russia's parliament, on 11 July. If approved, it would allow the government to set up an agency which would maintain a list of banned sites.
Visitors to Wikipedia are greeted with a message which, when translated, says: "The State Duma is expected to hold a second hearing about amendments to the Information Act, which could lead to the creation of extra-judicial censorship of the entire internet in Russia, including banning access to Wikipedia in the Russian language."
In a linked page explaining its decision, Wikipedia's authors go on to say the move "could become the basis for real censorship of the internet through the creation of a list of banned sites and IP addresses and the subsequent filtering of access to them".
Comparing the Russian plan to Beijing's attempts to block information on the internet that it deemed controversial, they added: "Lobbyists and activists who support these amendments claim that they are aimed exclusively against child pornography and 'similar types of content', but if one adheres to the provisions and stipulations of the suggested amendments they would lead to creation of a parallel to the 'Great Firewall of China' in Russia."