Infiltrative granulomatous pulmonary disease in northern West Pakistan was investigated with regard to its prevalence, degree of severity by roentgenographic criteria, and possible etiologies. One hundred eighteen unscreened men from the Peshawar area were examined by chest roentgenogram and tuberculin test. There was a 24.5% prevalence of roentgenographic abnormalities indicative of past or present infiltrative granulomatous pulmonary disease and a 79% rate of positive tuberculin reactions. A separate group of 118 men with roentgenographic evidence of calcified pulmonary lesions was given tuberculin, histoplasmin, coccidioidin, and blastomycin skin tests; there were 110 (93%) positive tuberculin reactions and no positive reactions to any of the fungal antigens. After relating these results to comparable studies reported from India, Burma, and elsewhere around the world, I concluded that there is no histoplasmosis, blastomycosis, or coccidioidomycosis in northern West Pakistan and that all or nearly all of the infiltrative granulomatous pulmonary lesions seen in this area are due to tuberculosis. Furthermore, on the basis of the unscreened group, between 3.4 and 10.2% of the adult male population at any given time has active pulmonary disease, undiagnosed and untreated.