To compare diagnostic values of CPH-I (Copenhagen Index), SMS (sonographic morphology scores), RMI (risk of malignancy index), and the combination of CPH-I and SMS. This retrospective research involves 143 patients with adnexal masses who were diagnosed and managed in our institution, including 99 cases (69.2%) with benign ovarian disease and 44 cases (30.8%) with ovarian cancer. The baseline characteristics and predictive measurable variables such as patient's age, menstrual status, serum CA125, HE4 results, and ultrasound reports were collected. We compared diagnostic values of CPH-I, SMS, RMI, and the combination of CPH-I and SMS. The area under the curve (AUC) of CPH-I, SMS, CPH-I + SMS, and RMI were 0.932, 0.916, 0.976, and 0.877, respectively. The suggested cutoffs of CPH-I, SMS, CPH-I + SMS, and RMI were 12.42%, 6.5, 0.6506, and 173.55, respectively. Moreover, the sensitivities in the prediction of ovarian cancer were 81.8%, 79.5%, 93.2%, and 84.1%, and the specificities were 96.0%, 89.9%, 93.9%, and 89.9%, respectively. The combination showed remarkably higher sensitivity in the differential diagnosis than other three predictive modalities, and higher specificity than SMS and RMI reported. It suggested that the performance of the combined modalities provides a more accurate methods in the preoperative diagnosis and differentiation of adnexal masses in women with high risk factors. However, the sensitivity, specificity, and positive predictive value of the combination of CPH-I and SMS require prospective evaluation and validation in a randomized, controlled trial settings in the future. Keywords Ovarian cancer. Copenhagen index. Ultrasound scoring. Risk of malignancy index This article is part of the Topical Collection on Medicine Electronic supplementary material The online version of this article (