Hibiscus rosa sinensis flowers, leaves and stembarks collected during winter, spring, rainy and summer seasons were hot extracted with benzene and screened for post-coital antifertility activity in female albino rats. Only flower portion showed significant activity which was maximum during winter followed by spring then rainy and minimum in summer season. The benzene extract of flowers of Hibiscus mutabilis, Hibiscus schizopetalus and Malvasicus grandiflorus, resembling H. rosa sinensis in petaloid structure and collected during their respective flowering season(s), failed to show any significant effect on pregnancy.