The raids, which started on September 30, have killed 1,015 civilians, including more than 200 children, the Britain-based Syrian Observatory for Human Rights said.
The group, which relies on a network of sources on the ground for its reports, said the strikes had also killed 893 Islamic State group fighters, and 1,141 other opposition militants, including members of Al-Qaeda affiliate Al-Nusra Front.
The total toll of 3,049 represents an increase of nearly 700 deaths in just three weeks.
But activists and rebels accuse Moscow of focusing more on moderate and Islamist opposition fighters than IS.
Russia has previously denounced accusations that its raids have killed civilians as "absurd" and said claims by rights groups of such deaths were made up of "cliches and fakes".
The Observatory says it differentiates between strikes by Russia, US-led coalition warplanes and the Syrian regime based on the type of aircraft and the munitions used.