A technique for continuous rearing of the red-banded leaf roller (Argyrotaenia velutinana (Walker)) in the greenhouse has been developed. Large numbers of larvae are produced daily with a minimum amount of labor by rearing in cages on Faba bean plants. When temperatures were maintained between 70° to 75°F. a generation was completed in 33 days. Eggs must be incubated at very high relative humidities and, to prevent diapause, the normal day length must be extended during larval development for the months of August through April. Granulosis and other diseases have been kept in check by following good sanitation practices. The original strain, started in July 1959, has been reared continuously for 20 months through 18 generations.