"When I Lost You" is a song with music and lyrics by Irving Berlin. It was written in 1912 after his wife of five months, the former Dorothy Goetz, died of typhoid fever. In it he poured out the grief of his loss; it was the only song that he ever admitted had such a connection to his own life. The song, a ballad, was unlike any of Berlin's previous songs, which were upbeat tunes written to take advantage of the dance craze. The song is in a slow waltz tempo.