Objective The aim of this study was to evaluate the individual and combined diagnostic value of five tumor markers in the elderly patients with pleural effusion. Methods Serum and pleural levels of cytokeratin fragment19(CYFRA21 1), neuron specific enalase(NSE), carbohydrate antigen15 3(CA15 3), carbohydrate antigen19 9(CA19 9) and carbohydrate antigen 125(CA125) were assayed in 32 elderly patients with malignant pleural effusions resulting from advanced lung cancer and in 30 elderly patients with benign pleural effusions by ELISA. Results Serum levels of CYFRA21 1, NSE, CA15 3, CA19 9 and CA125 in patients with malignant pleural effusions were (12 84?6 48) ?g/L, (22 07?11 25) ?g/L, (65 74?30 26) kU/L, (56 32?25 67)kU/L and (71 86?31 45) kU/L, respectively and were significantly higher than those patients with benign pleural effusions (P