"Russian planes did not carry out any combat missions, to say nothing of any air strikes, in the province of Idlib," Igor Konashenkov, a Russian Defense Ministry spokesman, said in a statement.
The Observatory had earlier said the air strikes targeted a number of positions in the city, one of them next to a hospital. Seven children were among the dead, Observatory Director Rami Abdulrahman said.
The Turkish foreign ministry said the strikes had killed more than 60 civilians and complained in a statement about what it said were the "indefensible" crimes of the Russian and Syrian governments.
Konashenkov called the Observatory's allegations "a horror story" of the kind he said it had disseminated in the past and said such pronouncements should be regarded with greater skepticism.
Idlib is a stronghold of rebel groups including the al Qaeda-linked Nusra Front.