 During this time he studied composition with Arthur Honegger and André Jolivet, and analysis with Olivier Messiaen at the same time as Pierre Boulez, Karlheinz Stockhausen, and Serge Garant.In the 1950s Pépin's compositions were performed by a number of symphony orchestras.He taught at the Conservatoire de musique du Québec à Montréal from 1955 to 1964 and later served as director from 1967 to 1973.