Purpose : The purpose of this study is to determine whether MR images after intravenous administration ofGd-DTPA can differentiate exudative and transudative pleural effusion. Materials and Methods : We studied 18patients with ten exudative and eignt transudative pleural effusions diagnosed clinically and by thoracentesis. Weanalysed the relationship between T1 value(normalized to fat) and the ratio of effusion/serum protein of pleuraleffusion. We also assessed the contrast enhancement of exudative and transudative pleural effusion on T1 weightedSE images taken at 15 and 30 minutes after administration of Gd-DTPA. Results : The relationship between theeffusion/serum protein ratio and T1 value(normalized to fat) was statistically not significant(r=0.27, P=0.381).On precontrast spin-echo T1W1, mean signal intensity of the transudate was 0.18 ($pm$0.04) and that of the exudatewas 0.24($pm$0.07), values which were not significant differences(P>0.05). Postcontrast mean signal intensities oftransudates at 15 and 30 were 0.20$pm$ 0.06 and 0.26$pm$0.08, respectively, values which were not significantly higherthan that of precontrast mean signal intensity(P<0.05). Postcontrast mean signal intensity values of exudativepleural effusions at 15 and 30 mimutes(0.32$pm$0.06 and 0.39$pm$0.06, respectively) were, on the other hand,significantly higher than that of precontrast mean signal intensity(P<0.05). Conclusion : Postcontrast T1-weightedSE images at 15 and 30 minutes can be helpful in the differentiation of transudative and exudative pleuraleffusion.