We studied fecundity and late sequelae of 39 women who had laparoscopic and microbiological sampling-proven acute pelvic inflammatory disease (PID) treated with the same antimicrobial regimen. The grade and etiology of index PID were classified using laparoscopy, endometrial biopsy and microbiological cultures from the cervix, endometrium and tubes: 20 had mild and 19 severe PID. The mean (SD) follow-up period after the index PID was 125 (44) [range 8-204] months. The primary end-point was pregnancy. All other or recurrent infections or other diseases related to the infection, including infertility, were evaluated. Twenty (51%) women had laparotomy or second laparoscopy during follow-up and findings were evaluated. Chlamydia trachomatis was isolated in 38% of all cases. Eleven (28%) of 39 women avoided conception or it was no longer possible. Twenty-eight women had tried to conceive after the index PID and 25 (89%) of them had at least one pregnancy. Twenty-five women had 56 pregnancies, 33 (59%) of which ended in delivery, 9 (16%) miscarried, 13 (23%) were induced abortion and only one (1.8%) tubal pregnancy occurred. Etiologic factors or severity of PID made no difference to the conception rate. Patients with mild or moderate salpingitis had a high conception rate. Endometriosis was found in 6 (30%) out of 20 women with second laparoscopy or laparotomy. Hysterectomy had been performed in 4 cases. Precise diagnosis of acute PID is the cornerstone for the treatment of the condition. Combination regimens, including drugs against the most common factors underlying acute PID against both aerobic and anaerobic microbes, prevent late sequelae in cases with mild or moderate salpingitis but not in cases with tubal or pelvic abscess.