In a 2-year prospective study, ninety adult patients with ascites at the University College Hospital Ibadan were evaluated clinically in addition to a diagnostic work-up protocol. Of these, 40 (44%) had liver cirrhosis, 21 (23%) had tuberculous peritonitis, 20 (22%) had ma-lignant ascites, 5 (6%) had heart diseases and 4 (5%) had nephrotic syndrome. Albumin gradient was compared with the usual parameters of ascitic fluid analysis in the differential diagnosis of ascites. We showed that the ascitic fluid total protein concentration, the ascitic fluid/serum total protein, the ascitic fluid lactic dehydrogenase, and the ascitic fluid/serum lactic dehydrogenase were lower in the patients with liver cirrhosis than in the patients with tuberculous peritonitis (p<0.0001) or malignant ascites (p<0.0001). In contrast, the albumin gradient (serum albumin minus ascitic fluid albumin) in the patients with liver cirrhosis was significantly higher than in the patients with tuberculous peritonitis (p<0.0001) or malignant ascites (p<0.0001). There was no difference in these biochemical parameters between the patients with tuberculous peritonitis and malignant ascites. Overall, the effi-ciency of the biochemical parameters in correctly diagnosing patients with ascites caused by liver cirrhosis and those due to tuberculous peritonitis or malignancies was highest for albumin gradient <1.1 g/dL (96%), followed by ascitic fluid lactic dehydrogenase level >180 IU/L (77%), ascitic fluid total protein >3.0 g/dL (73%), ascitic fluid to serum lactic dehydro-genase ratio >0.6 (70%) and ascitic fluid to serum total protein ratio >0.5 (63%). It is concluded that liver cirrhosis, tuberculous peritonitis and malignancies are the commonest causes of ascites in Ibadan. While this study shows albumin gradient the best diag-nostic discrimination between ascites caused by liver cirrhosis and ascites due to tuberculous peritonitis or malignant tumors, further studies on larger population in this environment is however indicated.