Abstract: Effects of Aspilia africana leaf extract on oestrous cycle and ovulation were studied in adult female Wistar strain rats. Cyclic female rats weighing 150 to 200 g were divided into two study groups: the oestrous study and ovulation study group. For the oestrous study, the experimental group received 500 mg kg-1 b. wt. of the extract for 14 days while the control group received distilled water for the same period. In both groups, vaginal lavage was taken daily from the 5th day to monitor the oestrous cycle. For the ovulation study, there was a control group and two experimental groups. The control group received distilled water while group 1 and 2 received 500 and 1000 mg kg-1 b.wt. of Aspilia africana leaf extract for 16 days, respectively. The animals were sacrificed on the estrous following the treatment. The results showed a significant decrease in the body weight of the treated rats (p = 0.01) and the oestrous cycle was altered after the commencement of extract. This was indicated by the prolonged proestrous and a reduced dioestrus and estrus. There was a dose-dependent reduction in the ovulation s shown by the reduced number of ova observed in the oviduct from the treated rats compared with control (p<0.05). The extract caused inflammation of the fallopian tube, degeneration in the ovarian cortex in the stroma cells of the ovary and disruption of the endometrium of the uterus. Results suggest that aqueous extract of Aspilia africana leaf has antifertility effect by altering oestrous cycle and causing a dose dependent adverse effect on ovulation in Wistar strain rats.