To transfer foreign genes into myoblasts in primary culture, we found cationic multilamellar liposomes to be a useful mediator. When the cells were transfected with 2 mu g of the plasmid pRSV-luc encapsulated into 50 nmol of our cationic multilamellar liposomes that had been prepared from N-(alpha-trimethylammonioacetyl)-didodecyl-D-glutamate chloride, dilauroyl phosphatidylcholine, and dioleoyl phosphatidylethanolamine in a molar ratio of 1:2:2, luciferase was expressed with high efficiency without cytotoxicity. When the cells were transfected with the plasmid pRSV-lacZ encapsulated into the same liposomes, 0.7% of the cultured myoblasts expressed beta-galactosidase without cytotoxicity. This is the first successful instance of introducing foreign genes into primary cultures of myoblasts by means of liposomes. (C) 1995 Academic Press, Inc.