In this study, pleural calcifications prevailing in the inhabitants of some villages and towns around Diyarbakir, a city in southeast Turkey, have been found to be caused by the inhalation of chrysotile asbestos, the mineral commonly used indiscriminately to paint the walls and floors of houses. There were no industrial establishments in the area, except some local mining, and asbestos deposits were even not included on the mining map of the country. Chest roentgenograms from the Chest Hospital and the tuberculosis dispensaries were screened: and, additionally, 15,239 photofluorograms were obtained during a survey. Of all these, 511 patients were found to have pleural calcifications, some with pericardial and diaphragmatic involvement. Forty-four percent (28) of the 64 patients who had examinations of samples of their sputa had asbestos bodies, and asbestosis was also induced in rabbits by administration of the raw material.