BACKGROUND: Ovarian disease is common in obese women and is usually not screened during routine preoperative evaluation in patients undergoing bariatric surgery. Consequently, surgeons may encounter previously undiagnosed adnexal tumors during bariatric operations. The aim of this study is to report our experience with incidental ovarian tumors in patients during Roux-en-Y gastric bypass (RYGBP). METHODS: Prospectively collected data on all consecutive patients undergoing RYGBP for clinically significant obesity from July 1998 to September 2003 were reviewed for patients with incidental gynecological tumors. Details of operative treatment and outcomes are reported herein. RESULTS: 460 women underwent RYGBP during the study period. 52 (11%) had a previous hysterectomy and/or bilateral oophorectomy and were excluded from the study. 12 ovarian masses, median tumor size 11 cm (range 4-65 cm) were found in 10 women (2.5%) during 6 open and 4 laparoscopic RYGBPs. Mean age was 40+/-9 years and mean BMI was 58+/-12 kg/m(2). Resection of 9 benign cystic lesions and 2 malignant lesions was undertaken. One patient with polycystic ovary syndrome did not undergo resection. The RYGBP was completed in all but 2 patients who, by appearance and intraoperative frozen biopsy, had evidence of malignancy. No additional morbidity resulted from the added gynecological procedure. Based on these results, an algorithm for the treatment of incidental gynecological tumors is suggested. CONCLUSIONS: Although infrequent, incidental ovarian tumors may be discovered in patients undergoing bariatric surgery, emphasizing the importance of thorough exploration of the abdominal cavity. Consultation with a gynecologist is warranted in most instances, and treatment should be on a patient-by-patient basis, especially in women of child-bearing age.