The SECOND largest religion or religious sect in the Russian Federation is?

Answer 1

Tatars are the second largest ethnic group in Russia after Russians.

Tatars can, however, be said to be largest minority ethnic group in Russia. Sometimes, when talking about "ethnic groups" or "ethnic population" people exclude the majority population from consideration. Only in that sense can Tatars be said to be the largest ethnic group in Russia.
Turkic is the second largest ethnic group in Russia after Slavic.

Answer 2

According to the United States Department of State, approximately 100 million Russian citizens citizens consider themselves Russian Orthodox Christians, amounting to 70% of the population, although only 5 percent of Russians call themselves practising. However the Orthodox Church claims a membership of 80 million.

According to a religiosity poll by the Russian Public Opinion Research Centre, 63% of respondents considered themselves Russian Orthodox, 6% of respondents considered themselves Muslim and less than 1% considered themselves either Buddhist, Catholic, Protestant or Jewish.

Another 12% said they believe in God, but did not practice any religion, and 16% said they are non-believers. Official census counter around 14.5 million. Russia also has an estimated 3 to 4 million Muslim migrants, both legal and illegal, from the ex-Soviet states. Most Muslims live in the Volga-Ural region, as well as in the North Caucasus, Moscow, St. Petersburg and western Siberia.

Buddhism is traditional for three regions of the Russian Federation: Buryatia, Tuva and Kalmykia. Some residents of the Siberian and Far Eastern regions, Yakutia, Chukotka, etc., practice pantheistic and pagan rites, along with the major religions. Induction into religion takes place primarily along ethnic lines. Slavs are overwhelmingly Orthodox Christian. Turkic speakers are predominantly Muslim, although several Turkic groups in Russia are not.

Answer 3

Islamic religion

Answer 4

Islam