Ovarian cancer is the most frequent cause of death from all gynaecological malignancies because of its insidious onset, vague symptoms and late presentation. This cross-sectional study was carried out on purposively selected 43 patients with suspected ovarian tumor in the Department of Radiology and Imaging in collaboration with the Department of Gynaecology and Obstetrics and Department of Pathology, Mymensingh Medical College Hospital, Bangladesh from January 2015 to December 2016 to assess the diagnostic performance of color Doppler ultrasonography and CA-125 in a combination described as Novel Index in detection of ovarian tumor. Highest number of patients of ovarian tumor 10(23.26%) were in age group 35 to 44 years and 45 to 54 years with a mean of 37.72±15.65 years with a range of 8-70 years. Histopathology findings revealed 19(44.18%) benign tumors and 24(55.82%) malignant tumors. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of Resistance Index (RI) in diagnosis of ovarian tumor were 91.67%, 89.47%, 91.67%, 89.47% and 90.69% respectively. Sensitivity, specificity, PPV, NPV and accuracy of serum CA-125 were 83.33%, 89.47%, 90.90%, 80.95% and 86.04% respectively. Sensitivity, specificity, PPV, NPV and accuracy of Novel index were 95.83%, 89.47%, 92.00%, 94.44% and 93.02% respectively. Novel index showed better diagnostic performance. Based on the current study it is concluded that the combination of color Doppler ultrasonography and serum CA-125 can be useful for diagnosis of ovarian tumor.