A self-sustaining colony of common marmosets, Callithrix jacchus, was established for reproductive research. Methods of management were developed to ensure optimal breeding conditions for marmosets in captivity. Studies of the reproductive biology and endocrinology of this species suggest that the common marmoset may be a suitable model for the human in certain aspects of the ovarian cycle, pregnancy, puberty and the hypothalamic and pituitary control of luteinizing hormone secretion. The rapid rate of reproduction of C. jacchus in captivity allows a relatively large colony to be maintained at moderate cost and also makes this species a most suitable laboratory primate for longer term studies of the safety and efficacy of new contraceptive methods.