Quasi-azeotropic or azeotropic compositions containing chloromethane and at least one or more compound(s) selected from 2,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene, 1,1,1,2-tetrafluoroethane, 1,1,1,2,2-pentafluoropropane, E/Z-1,1,3,3,3-pentafluoropropene, E/Z-1,2,3,3,3-pentafluoropropene, 1,1-difluoroethane and E-1,3,3,3-tetrafluoropropene. The composition may include either from 0.5 to 70 mol % of chloromethane and at least from 99.5 to 30 mol % of a compound selected from 2,3,3,3-tetrafluoropropene, 1,1-difluoroethane, 3,3,3-trifluoropropene and 1,1,1,2-tetrafluoroethane, or from 55 to 95 mol % of chloromethane and at least from 45 to 5 mol % of one or more compound(s) selected from 1,1,1,2,2-pentafluoropropane, E/Z-1,1,3,3,3-pentafluoropropene, E/Z-1,2,3,3,3-pentafluoropropene and E-1,3,3,3-tetrafluoropropene.