Mitrofan (Mitrophan) Yefimovich Pyatnitsky (Russian: Митрофан Ефимович Пятницкий) was a Russian and Soviet musician, gatherer of Russian folk songs. He established the famous Pyatnitsky Choir in 1910 from 18 peasants originally from the Voronezh, Ryazan and Smolensk gubernias. After his death in 1927, the chorus was named after him.