A comparison of various biochemical parameters used in differentiation of nature of pleural effusion in transudate and exudate was done in 84 patient of pleural effusion. Pleural fluid (P) cholesterol and bilirubin which have gained an importance in recent years were compared with pleural fluid protein, LDH, P/S protein, P/S LDH and Light's criteria. It was seen that Light's criteria is still the best in differentiation. Sensitivity of individual test was nearly same for Pl. protein (94.11%), P/S Protein (94.11%), Pl. LDH (95.5%), P/S LDH (92.75%). Pl cholesterol (88.3%) and P/S cholesterol (91.42%) had slightly lower sensitivity. Pl. Protein and P/S LDH had 100% specificity. Lights criteria had 100% specificity and sensitivity % of cases misclassified by various criteria were Pl Protein 5.95%, P/S protein 5.95%, PLDH 4.76%, P/S LDH 4.76% P. Cholesterol 13% and P/S Cholesterol 9.52% Measurement of Bilirubin did not provide any correlation in classifying the effusion and thus did not hold any value.