To investigate the criteria for laparoscopic surgery in ovarian tumors, a retrospective review of indications, preoperative assessments using transvaginal ultrasonography, serum CA 125, surgical methods and diagnosis and post-operative complications were analyzed. Forty-three patients underwent surgical treatment for ovarian tumors, from November 1992 to October 1993. Of the 43 patients with ovarian tumors, 19 (44%) underwent laparoscopic surgery, and 24 (56%) underwent laparotomy. Laparoscopic surgery was performed in 18 of 34 (53%) patients with benign ovarian cysts. Eight patients with malignant ovarian tumors were treated by laparotomy. Coincidence of preoperative assessment and surgical diagnosis was 95%. No major complications were observed in the laparoscopic surgery. We suggest that malignant ovarian tumors and inextricable adhesions are contraindications to laparoscopic surgery. We propose the following criteria for laparoscopic surgery by classification into three groups: A) good indication: benign cystic tumors with good mobility, B) deliberation indication: benign tumors with poor mobility, including some dermoid cysts and endometrial cysts, C) contraindication: malignant tumors and dense adhesions. We conclude that indications of laparoscopic surgery for ovarian tumors should be determined by careful preoperative assessment using transvaginal ultrasonography and tumor markers.