Endoscopic ovarian surgery is currently spreading tremendously, but also rather uncritically. The technical possibilities both of organ preserving and ablative endoscopic surgery are controversial, so that structuring of the indication for an endoscopic procedure as well as optimization of the endoscopic removal of ovarian tumor or adnexae is of utmost relevance. Therefore, a study was performed at the Department of Obstetrics and Gynaecology of the Heidelberg University with the following aims: Risk evaluation of operating into an ovarian malignancy at endoscopy for "presumably" benign cystic ovarian tumors in n = 100 cases in Heidelberg and literature survey Analysis of problems and complications during clinical application of laparoscopic lap sacs for removal of cystic adnexal tumors or adnexae (n = 50) Experimental examination of the risk of an endoscopic lap sacs to rupture during a procedure The risk of endoscopically operating into an ovarian cancer lies between 0.4 and 3% according to literature data. Despite maximal preoperative selection, mainly by ultrasound examination, in our group of 100 patients, in three women without preoperative signs of malignancy but with discreet intracystic structures in the ultrasound, an endoscopic adnexectomy with complete removal in a lap sac was performed, and though immediate section for microscopic examination was negative, final histology revealed one ovarian cancer la and 2 borderline tumors, same stage. In the time period analyzed, three further patients were referred to our center for secondary, delayed (median 3 months) staging after endoscopic procedures for presumed benign lesions. Clinical application of lap sacs proved the necessity of an intensive training. In 3 patients an intraperitoneal rupture of the sac occurred. Typical problems were volume discrepancies between sac respectively abdominal incision and tissue to be removed (28% of cases). The risk of rupture of the various lap sacs examined differed significantly (p < 0.05). Due to the complex pathological nature of cystic adnexal tumors, a 100% selection for the endoscopic approach is not feasible. Therefore, an endoscopic procedure should only be performed after optimal preoperative diagnosis and, in case of the slightest doubt, only if intraoperative microscopic examination is available, and the possibility to perform an immediate staging laparotomy. Sufficient information of the patient is relevant. Laparoscopic removal of tumor or adnexae should be performed in a lap sac. However, there is no absolute certainty of preventing spillage even with the lap sac, since not all endoscopic sacs available are of a sufficient quality.