Changes in ovarian function were evaluated in 43 women, before and after tubal ligation. Midluteal endocrine profiles and endometrial biopsies were investigated before and at 3, 6 and 12 months after the operations. During postoperative follow-up there was significant increase in luteal phase deficiency and midluteal FSH, LH and E2 levels (p < 0.001). Progesterone levels significantly decreased (p < 0.001) and anovulation was observed in 13 (30.2%) of 43 cases. Our data suggest that tubal sterilization carried increased risk in ovarian function, particularly luteal phase deficiency and anovulation.