Esophageal cancers linked to lifestyle and environmental factors appears to possess varying abilities to produce Carcinoembryonic Antigen (CEA), hence in this study the diagnostic precision of CEA in patients initially diagnosed of esophagus cancer before receiving any anticancer therapy was evaluated. Serum CEA levels were assessed in healthy subjects and patients initially diagnosed of esophageal carcinoma by endoscopic examination and biopsy (N=50 each), both categories including male and female smokers and non-smokers. The test was performed by two site sequential Chemiluminescent Immunometric assay kit. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) of CEA was found out and Receiver Operating Characteristic (ROC) curve plotted. Serum CEA levels were significantly higher in esophagus cancer patients as compared to control and in healthy smokers as compared to non-smokers. The overall sensitivity and specificity of CEA for detecting esophagus cancer was 38% and 80% respectively. The AUC was 0.772 (SE=0.04) and significance level P<0.0001. PPV was 65.51% and NPV was 56.34%. Using ROC curve analysis the optimum CEA cut-off point for the best combination of sensitivity 66% and specificity 86% was > 2.81 ng/ml. The CEA positivity rate before therapy was 38% which dropped to 18% after therapy. Serum CEA is a test with high specificity but insufficient sensitivity for detecting esophageal cancer in isolation. However, it may help as an additional parameter in screening the risk groups and monitoring of palliative therapy.