Background: Hymenocardia acida is traditionally used in African herbal medicine and has numerous therapeutic benefits. But little is known about its potentially negative effects on pregnant women. Objective: The aim of the present study was to evaluate the antifertility effect of aqueous ethanolic extract of Hymenocardia acida stem bark in female Wistar rats. Materials and Methods: Four groups of rats were administered orally aqueous ethanolic extract of Hymenocardia acida at doses of 100, 200 and 400 mg/kg body weight daily for 19 days. The control group received distilled water. On day 20 of gestation, each rat was laparatomised and number of corpora lutea of pregnancy, number of live fetuses as well as the postcoitum fertility index, weights of the foetuses and placentae were determined. Results: Oral administration of the extract from days 1 to 19 of gestation showed reduction (p<0.05) in the number of corpora lutea of pregnancy and number of live fetuses. Weights of fetuses of extract treated female rats were also smaller (p<0.05) compared with the control. Anti-implantation activity of the treatment groups were 41.4%, 48.3% and 51.7% for groups II to IV respectively, whereas antifertility activity of the groups was found to be 40%, 60% and 60% in the same order. Conclusion: The results suggest that aqueous ethanolic extract of Hymenocardia acida stem bark could induce negative effects on reproductive functions in female albino rats