Mitrofan (Mitrophan) Yefimovich Pyatnitsky (Russian: Митрофан Ефимович Пятницкий; 3 July [O.S. 21 June] 1864 – 21 January 1927) 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, the chorus was named after him.