This research was undertaken to observe the antifertility potential of neem oil in males and females , 96 albino rats were used in this study. The animals were administered with two different doses of neem oil orally once at the beginning of study. The animals were divided in different groups (A) treated female with treated males, (B) untreated females with treated males, (C)treated females with untreated males and(D) untreated females with untreated males (Control).They left in the same cage for a period of six weeks. The blood was drawn by cardiac puncture, for the estimation of serum concentration of reproductive hormones in male and females including FSH, LH, Estradiol, Progesterone and testosterone. Animals were scarificed and the female and male gonads were removed for the histological study and analytical purpose to determine the quantity of the active components in tissues. Hormonal analysis revealed significantly increased levels of FSH in low and high dose treated females and significantly decreased levels of estradiol and progesterone in animals treated at high dose. In the males significantly decreased hormone levels were only found amongst high dose treated animals. HPLC has demonstrated the presence of high concentration of neem compounds Azadirachtin & Azadirichtinin in the ovaries. In males these compounds have been shown in high concentration as compared to control males but with much in less concentration as compared to treated females. The histological sections of the gonads have also revealed significant decrease in the number of mature follicles in females and seminiferous tubular diameter in males in the treated animals. None of the females treated at high dose conceived during the present study. From these findings it can be concluded that neem oil has a dose depended antifertility potential.