Boris Ivanovich Fomin (12 April 1900 – 25 October 1948) was a Russian and Soviet musician and composer known for his work in the Russian romance genre. Born in Saint Petersburg, Fomin showed an early talent for music, playing the accordion by age four. He studied piano under Anna Yesipova at the Saint Petersburg Conservatory, though his education was interrupted by the 1917 Revolution.

In 1918, Fomin moved to Moscow and volunteered for the Red Army, where he entertained troops during the Civil War. He began his musical career in the early 1920s, writing music for operettas and ballets, but he gained fame as a songwriter. His most notable composition is "Dorogoi dlinnoyu" ("By the Long Road"), which became internationally famous as "Those Were the Days" after being adapted with English lyrics by Eugene Raskin in 1962. The song was originally recorded by Tamara Tsereteli and Alexander Vertinsky in the 1920s.

Fomin's music, characterized by its soulful melodies, was often mistaken for folk or gypsy music. Throughout his career, he wrote around 200 songs, many of which were performed by leading Soviet singers. Despite facing challenges from the Bolshevik regime, which was suspicious of his genre, Fomin's work left a lasting legacy in Russian music. He passed away in Moscow in 1948 and was buried at Vvedenskoye Cemetery.