The aim of the study was to evaluate the role of ascitic fluid fibronectin in the diagnosis of malignant ascites. Fibronectin is a glycoprotein which plays an important role in regulating the organisation of the cell cytoskeleton and cell morphology. Ascitic fluid samples from 35 patients, 20 with portal hypertension (Group-I) and 15 with malignant ascites (Group-II) were analysed for proteins, cell counts, fibronectin levels and malignant cell cytology. Mean ascitic fluid fibronectin level was found to be significantly higher in malignant ascites as compared to portal hypertension (p < 0.001). At a cut off value of 94.67 microg/ml, the sensitivity, specificity, positive accuracy, negative accuracy and overall diagnostic accuracy was found to be 100%, 95%, 93.8%, 100% and 97.1% respectively.