From January 1975 to December 1991, 34 patients with a diagnosis of epithelial ovarian tumors of low malignant potential (LMP) were admitted to the Istituto Nazionale Tumori of Milan. Eighteen of them (group 1) underwent complete staging laparotomy and retroperitoneal para-aortic and pelvic lymphadenectomy, as for ovarian cancer. In the remaining 16 cases (group 2), the surgical treatment ranged from unilateral oophorectomy to incomplete staging procedure. In group 1, nine patients (50%) were found to have retroperitoneal nodal involvement. In group 2, all patients had stage I disease. Patients were followed up for 20-222 months (mean 108, median 86). There were two recurrences in group 2 (after 5 years) and none in group 1 (NS). Currently all patients are alive and disease free. Nine of 18 group 1 patients were upstaged to stage III on the basis of lymph node involvement only. However, at least in this retrospective series, lymph node metastases did not affect prognosis or survival.