The objective of this study was to determine visual quality, diagnostic accuracy, and surgical merits of small diameter laparoscopy (SDL). Thirty-seven patients were randomly selected. The indications for laparoscopy were infertility, desire for tubal sterilization or chronic pelvic pain. Patients underwent SDL, followed by conventional laparoscopy (CL) as a control under general anaesthesia. Findings at operation were compared. The mean time for diagnostic work-up was longer with SDL than CL, 11.7 +/- 5.6 versus 7.6 +/- 3.2 min respectively (P < 0.04). Visual quality was scored from 4 to 1 by the operator; mean visual quality, mean endometriosis score and mean adnexal adhesions score were slightly lower with SDL than CL. Sensitivity of SDL in diagnosing endometriosis, adhesions, ovarian, uterine and pouch of Douglas lesions were 71, 58, 81, 89 and 73% respectively; specificity was 100, 96, 100, 100, 100% in the same order. Suction irrigation, cyst aspiration, tissue biopsies, simple adhesiolysis, tubal ligation and cauterization were easily performed with SDL. We conclude that SDL seems a good alternative to CL in diagnosing macro-pelvic anatomy and coarse pelvic pathologies and may also be good in performing surgical procedures such as: tubal ligation, biopsies and differential diagnosis of pelvic fluids. But SDL must be used cautiously in micro-oriented, functional conditions such as infertility, pelvic pain, endometriosis and adhesion scoring or treatment. SDL may be regarded as a less invasive but less sensitive tool with limited surgical merits.