Background: Incidence of endometrial cancer in India is increasing due to lifestyle changes and obesity. As 5 year survival rate of cancer confined to uterus is good, there is need for serum tumor marker for early diagnosis. This study was designed to identify a tumor marker which differentiate endometrial carcinoma and abnormal uterine bleeding (AUB) because common presentation of endometrial carcinoma is AUB. Objectives: To estimate and compare serum prolactin, Cancer Antigen 125 (CA-125), Cancer Antigen 15-3 (CA15-3), and Carcino embryonic antigen (CEA) levels in patients with endometrial cancer and abnormal uterine bleeding; To evaluate the role of these markers in diagnosing endometrial cancer. Methodology: Thirty eight patients with endometrial cancer and 40 patients with AUB were recruited in this study. Serum prolactin, CA 125, CEA, and CA 15-3 levels were estimated in both groups. Results: The levels of CA 15-3, CA 125, CEA, and prolactin were increased in endometrial carcinoma patients, on comparison with AUB patients. CA 125 alone was found to be a better marker to detect endometrial cancer with 52.63% sensitivity, 80.00% specificity. Conclusion: As individual tumor marker, serum CA 125 has the ability to detect endometrial cancer in patients with abnormal uterine bleeding.