Report is made on three cases of benign asbestosic pleural effusions that occured in subjects of more than 60 years in age that had had moderate but long occupational contact with asbestos (between 18 and 40 years). We are dealing here with pleural effusions that have an insidious onset and a chronic course, serofibrinous in nature for the three cases, moderately exsudative, with a relatively few accelerated blood sedimentation rate, a level of protids between 34 and 58 g/l and a level of dextrose between 0,70 and 1,15 g/l. Relapses were noted in two of the patients. In two of these cases existed associated pleural calcifications. Important sequelae persist after the cure that consist in pachypeuritis, and one of these cases was submitted to surgery. Confirmation of the diagnosis was found in the surgical material that contained asbestosic bodies; the sputum of the same patient contained also ferruginous bodies. The research of an occupational contact with asbestos has to be systematically performed in the case of subjects that exhibit, after a certain age, an apparently cryptogenetic pleural effusion.