Communist Party leader Vladimir Zyuganov and several lawmakers officiated at the ceremony, presenting the new members with the traditional red neckerchiefs worn by schoolchildren since the founding of the movement in the Soviet Union 87 years ago.
Zyuganov told the crowd: "You, tying your red neckerchiefs, have taken on the responsibility of fulfilling the best traditions of our great Soviet nation."
"I congratulate you, thank you for this responsible step, and hope that you will with honor declare your loyalty to the red banner."
The children then chanted in full the motto of the movement.
Pioneers' Day was officially celebrated on in the Soviet Union on May 19, but ceased to be an official holiday after the collapse of communism. The movement was founded by the Komsomol (Soviet Youth Union) in 1922.
After the celebrations, Pioneer members laid flowers outside Lenin's mausoleum, and several had their photographs taken with Zyuganov.
