In the past decades, the therapeutic use of anabolic androgenic steroids (AAS) has been overshadowed by illicit abuse of these drugs by athletes and non-athletes. Consequently AAS can have adverse effect like coronary heart diseases, reproductive and endocrine disturbances. The present investigation was undertaken to determine the efficacy of one of the AASs stanozolol on the maintenance of pregnancy in Swiss albino mice. Normal pregnant mice were assigned to three experimental groups. Two groups received stanozolol through sc. (0.5mg/kg bwt/day in 3% alcohol) from day 8 through 14 or 19 of pregnancy. Control animals received vehicle alone (3% alcohol). The results revealed that treatment of stanozolol is not able to maintain gestation to full term, resulting in partial fetal resorption with many placentomas, placental scars and no viable fetuses indicate the functional failure of corpus luteum. Histomorphology and differential follicular count revealed a noticeable decrease in secondary and antral follicles, increase in atretic follicles and an insignificant reduction in the number of corpora lutea in both treatment groups. It is concluded that stanozolol interrupts pregnancy and its effect may be mediated through reduction in the developing follicles and principally due to the deficiency of luteal hormones.