"Over many centuries this festival has given people the unfailing light of faith, hope and love," the presidential letter released by the Kremlin read. "Christmas festivities bring conciliation, good intentions, mercy and mutual respect into our lives."
Some 110,000 people attended Christmas services in Moscow alone, said Anatoly Lastovetsky, a spokesman for the Interior Ministry's department in the Russian capital.
Metropolitan Kirill, the interim leader of the Russian Orthodox Church since the death of Patriarch of Moscow and All Russia Alexy II in December, led the festive service at Cathedral of Christ the Savior in central Moscow.
There are more than 800 Orthodox churches in Moscow, and over 29,000 subordinated to the Russian Orthodox Church across the globe.
The Jerusalem, Serb and Georgian Orthodox churches, as well as monasteries on Mount Athos, Eastern Catholics and some Protestants following the Julian calendar, also celebrate Christmas on January 7.