Clinicians are urgently searching for ways of differentiating a malignant from a benign ovarian mass. How to approach or what is the prognosis? Some have shown the CA-125 test combined with ultrasonography to be highly sensitive and specific, when compared to single parameter. We examined 238 patients who underwent laparotomy for adnexal mass. Of these 44 were found to suffer from malignant tumors and 194 from benign lesions. Before the operation, CA-125 level was measured; pelvic ultrasonography was performed on each patient and the sonographic data were evaluated on an echostructural scoring system. After a sophisticated computer assisted analysis, the results of the combined tests were CA-125 greater than or equal to 65 U/ml or US score greater than or equal to 8 with a sensitivity of 77.3%, a specificity of 81.4% and a diagnostic accuracy of 80.7%. Therefore we confirm that CA-125 may be considered as a useful adjunct to sonography in the differential diagnosis of adnexal mass.