Objective: Anti-fertility activity of ethanolic extract of Jatropha gossypifolia leaf in female albino mice. Methods: Jatropha gossypifolia leaf extract, when administered orally, altered the estrous cycle pattern in female mice, prolong the length of estrous cycle with significant increase in the duration of diestrus stage and reduced significantly the number of litters in albino mice. Treatment of mice with extract of 250 and 450 mg/kg body weight/day for 21 days caused a prolonged estrous cycle with significant increase in the duration of diestrus phase and elongation of estrus stage in treatment with higher dose (450 mg/kg body weight/day). Results: The analysis of the principal hormones involved in estrous cycle regulation showed that the plant extracts altered gonadrotrophin release (LH, FSH and prolactinn) and estradiol secretion. Conclusions:The results indicated the anti-fertility effect of Jatropha gossypifolia leaf extract in female albino mice.