Since a technique for mass rearing of the cabbage maggot Hylemya brassicae (Bouché), was described (Read, 1960), inquiries from different countries indicate that many workers encounter difficulties in rearing this insect in captivity. This paper discusses these difficulties and describes methods successfully used by the authors for establishing and maintaining cultures in the greenhouse. Using these methods, 22 successive generations of H. brassicae have been reared at Belleville in less than four years.