The seed powder of Abrus precatorius L. has traditionally been used as oral contraceptive agent bythe women in some rural areas in Bangladesh. The present study aimed to examine the antifertilityactivity of A. precatorius seed extracts in experimental female rats. Finely ground seeds wereextracted with aqueous acetone followed by successive partitioning with n-hexane, ethyl acetate(EtOAc), methanol (MeOH) and water. Water suspended crude seed powder, organic fractions ofacetone extract and a standard contraceptive drug (Nordette®28) were separately administeredorally to the female rats for 30 days. n-Hexane, EtOAc and MeOH solubles at the doses of 2, 4 and 6mg/rat/day, respectively and crude seed powder at 100 mg/rat/day exhibited 100% antifertilityactivity with lowest levels of serum luteinizing hormone (LH), follicle stimulating hormone (FSH)and 17β-estradiol. Histological study of ovary and uterus of these rats exhibited reduced number ofdeveloping follicles and increased number of atretic follicles in the ovary, and fewer uterine glandswith shrunken morphology, reduced endometrial height, poor vascularity and compact stroma inuterus. However, the activities of serum glutamate oxaloacetate transaminase and serum glutamatepyruvate transaminase and the body weight of the rats remained almost unaffected in all the seedextract treated rats compared to control. These results suggest that A. precatorius seed extractsreduced the levels of serum FSH, LH and 17β-estradiol probably by affecting hypothalamic-pituitary-gonadal axis. The reduced levels of these hormones might have affected the oestrouscycle, follicular development, and subsequently the establishment of pregnancy in treated rats.