Background. The aim of the study was to determine the role of laparoscopic ultrasonography in the management of ovarian cysts extirpated by means of endoscopic surgery. Methods: Laparoscopic ultrasonography was used during endoscopic surgery in 14 consecutive patients with an adnexal mass. The diagnostic accuracies of transvaginal and laparoscopic ultrasonography were compared according to the final pathological diagnosis. Estimations of the exact location of the ovarian mass by means of laparoscopic visualization and laparoscopic ultrasonography were compared. The presence of residual tumor tissue after cyst extirpation was monitored with laparoscopic ultrasonography. Results: Using laparoscopic ultrasound and transvaginal ultrasound the correct diagnosis was made in 12 of 14 (85.7%) and 9 of 14 (64.3%) patients, respectively (not significantly different). With laparoscopic visualization, the exact location of the ovarian tumor could be demonstrated in 57.1% (8/14) of the cases, while with laparoscopic ultrasonography precise visualization of the ovarian mass was achieved in all cases (not significantly different). Two patients were found to have residual tumor tissue in the ovary when laparoscopic ultrasonography was performed again after tumor extirpation. Conclusion: Laparoscopic ultrasonography seems to be useful in patients with an adnexal mass managed by endoscopic surgery, in terms of evaluating the internal characteristics and predicting the histological diagnosis of the ovarian cyst, deciding on the correct placement of the incision to prevent unnecessary trauma to the ovary, and evaluation of the ovary after cyst extirpation to expose any residual tumor tissue. Copyright (C) 2005 S. Karger AG, Basel.