Moscow's first large
Hundreds of people are expected to attend the event, which will start with a march on Nikitsky Bulvar at about 7 p.m. and continue with a rally on Pushkin Square in downtown Moscow.
The demonstration, organized by anti-fascism activists, was sanctioned by the city authorities.
Other rallies are planned to take place in 19 other cities across Russia.
Markelov and Baburova, who was a freelance reporter with Novaya Gazeta, were killed near the Kropotkinskaya metro station after a news conference on Jan. 19, 2009.
Two nationalists were jailed over the killing last year. Gunman Nikita Tikhonov was sentenced to life in prison, while his accomplice and girlfriend, Yevgenia Khasis, got 18 years.
The organizers of Thursday's rally released a series of videos that feature prominent human rights activists and journalists calling on the public to participate in the event.
More than 20 people were detained last year at the demonstration, which was authorized by City Hall.