Four hundred ninety-eight consecutive new female patients in a private obstetrics-gynecology practice were asked about their coital habits during menses (SxMs/F = frequent, SxMs/O = occasional, SxMs/N = never) and history of pelvic inflammatory disease (PID). Endometriosis and tubal infertility factor were diagnosed on laparoscopy or laparotomy. The frequency of endometriosis was higher (P less than .05) in patients with coitus during menses (SxMs/F + O) (17.5%) than in the SxMs/N group (10.9%). The frequency of PID was not different between the SxMs/F + O (10.8%) and SxMs/N (9.7%) groups. Thirty-five percent of the infertility patients had a tubal infertility factor. The frequency of tubal infertility factors was higher in the PID group (78.4%) than in the non-PID group (30.4%) (P less than .001). Endometriosis was associated with an increase in tubal infertility factors (47.9% vs. 33.3% in the nonendometriosis group) but to a lesser degree than PID. The frequency of PID in the group with a tubal infertility factor was higher (22.7% vs. no tubal factor, 3.4%) (P less than .001), and the frequency of endometriosis was higher in the group with a tubal infertility factor (19.3% vs. no tubal factor, 11.5%) (P less than .05). Coitus during menses appeared to increase the chances of endometriosis but not of PID. The rate of tubal infertility factors increased in both PID and endometriosis.