Introduction: The serum CA125 level is found to be most useful tumor marker in diagnosis of ovarian tumours. Objective: The aim of the present study was to evaluate preoperatively CA125 levels in suspected ovarian tumours, and compare it. Materials and methods: 100 ovarian tumour cases was included in the study. Preoperative serum CA125 levels were measured. Histopathological diagnosis was made and the tumours were categorized into Benign, Borderline and Malignant. CA 125 levels were compared. Results: Among the 100 ovarian tumour cases, the majority were benign comprising of 76 cases (76%), 3 (3%) were borderline and 21 (21%) malignant. The mean CA 125 levels of benign, borderline and malignant tumours were found to be 23.63 ± 14.74 , 130 ± 28.28 and 302.17 ± 193.42 respectively with p value of <0.0001. Conclusion: Significant correlation was found between benign and malignant groups with p value < 0.0001. It serves as valuable tool as early diagnostic & prognostic marker.