Objective: To study the value of combined determination of carcinoembryonic antigen (CEA), total cholesterol (Tch) and adenosine deaminase (ADA) in the differential diagnosis of ascites due to different causes. Methods: Sixty-eight cases with ascites were divided into 3 groups based on their etiology, namely malignant ascites, tubercular ascites and non-tubercular benign ascites. CEA, Tch, and ADA were measured and analyzed in different ascites.Results: CEA was significantly higher in malignant ascites than in benign ascites, the sensitivity and spedfidty for malignant ascites being 50％ and 100％ respectively. Tch is higher or equal to 1.54 mmol/L in tubercular ascites and lower or equal to 1.18 mmol/L in non-tubercular benign ascites, and Tch level in malignant ascites was frequently between that in tubercular acites and non-tubercular benign ascites. Ascitic fluid ADA activity was higher than 30 U/L in 80％ of tubercular ascites, while none of non-tubercular benign ascites reached to such level. Conclusion: CEA, Tch and ADA are valuable for the diagnosis and differential diagnosis of ascitic etiology and combine measurements of these indices can increase the diagnostic efficiency.