Ovarian masses are a frequent cause of gynaecological malignancy. The risk of the Malignancy Index (RMI) is widely studied for the prediction of malignant pelvic masses. The objective of this study was To determine the diagnostic accuracy of RMI in diagnosing ovarian masses preoperatively for malignancy keeping histopathology as the Gold standard.it was a Cross-sectional study conducted in Gynae and Obs unit 1 Fauji Foundation Hospital Rawalpindi. Duration of study was months after approval of synopsis, non-probability consecutive sampling was used approval obtained from ethical committee. A total of 87 expected patients of having ovarian masses reporting in outpatient (OPD) and were admitted in wards were enrolled for the study. Informed written consent was taken from all the patients. Ultrasonography (USG) and serum CA-125 levels of all the patients were done and scores were assigned to each parameter. The RMI was calculated for each patient. Histopathology was obtained and all the information was recorded on a predesigned Performa. RMI 25(28.7%) had positive and 62(71.3%) had negative findings. On histopathology findings, there were 25(28.7%) malignant and 62(71.3%) were benign masses. The sensitivity, specificity, PPV and NPV of RMI was 92%, 96.77%, 92% and 96.77% with a diagnostic accuracy of 95.4%. The likelihood ratio for positive and negative was 28.52 and 0.082 respectively. RMI is a highly sensitive (92%) and specific (96.77%) method to identify ovarian carcinomas.