OBJECTIVE: To determine the accuracy of subjective sonographic assessment in distinguishing between benign and malignant adnexal masses. STUDY DESIGN: Cross-sectional descriptive study. METHODS: The patients scheduled for elective surgery due to adnexal masses were recruited into the study. All patients were sonographically examined within 72 hours of surgery were subjectively evaluated by the experienced sonographer, who had no any information of the patients, to differentiate between benign and malignant adnexal masses based on sonographic morphology. The final diagnoses, used as gold standard, were based on either pathological or operative findings. RESULTS: One hundred and fifty-eight patients with 174 adnexal masses, (benign; 108 and malignant; 66) were recruited into the study. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were of 89.7%, 84.9 % and 92.6 %, 87.5% and 90.9%, respectively. CONCLUSIONS: Subjective evaluation of sonographic morphology has high accuracy in differentiating between benign and malignant adnexal masses.