An investigation was carried out to study the teratogenic effect and sexual development of melatonin treatment on Bauscat rabbit offspring. Results obtained revealed that pregnant doe rabbit injected with 50 or 75mg/kg body weight suffered from low implantation sites and the high percentage of resorbed foeti. Concerning the foetal malformation, the foeti were malformed in their skull, vertebral column, ribs and pelvic bones, as well as, fore and hind limbs. However, melatonin injection with 25mg/kg for doe did not prove teratogenic effect on rabbit embryos. The highest frequency of overdue does showed after injection with any dose of melatonin. The mother's melatonin treatment can act on offspring sexual development.