The management of a woman having adnexal mass is a problem frequently faced by the gynaecologist. It may represent a wide and varied differential diagnosis including both benign and Malignant gynaecological condition and also some non gynaecological conditions. In clinically diagnosed adnexal mass traditional strategy for establishing final diagnosis has been to perform an exploratory laparotomy. Ovarian Malignancy is an important Adnexal pathology. In practice, the diagnosis of ovarian malignancy is often difficult to make preoperatively & consequently many women do not receive appropriate first line surgery, Therefore sensitive and specific methods for diagnosis of ovarian malignancy is needed. This will determine the type of surgery, pre operative preparation and may influence the selection of institution and expertise of surgeon. The risk of malignancy index (RMI) is a simple but novel scoring system introduced by Jacobs et al (1990) utilizing 3 diagnostic criteria-ultrasoundfindings, s.CA125 level and menopausal status. My study was to validate role of RMI to discriminate malignant from benign adnexal mass in new population.