Two-hundred pigeon breeders attending a national convention were studied for a possible correlation between the hobby of raising pigeons and the incidence of respiratory or immunologic abnormalities. Information concerning his exposure to pigeons, respiratory symptoms and smoking habits was obtained from each breeder. Chest x-ray examinations and pulmonary function tests were also obtained, and sera were examined for the presence of precipitating antibody against pigeon antigens. Precipitating antibody was detected in 40 percent of the breeders, and its presence could not be correlated with any of the variables, except with the duration and degree of exposure to birds. No cases of pigeon breeders' disease were detected, and there was no correlation between respiratory symptoms, abnormal pulmonary functions or chest x-ray films, and degree of exposure to pigeons. These results suggest that the tested group of pigeon breeders probably did not significantly differ from the general population except for the presence of precipitins against pigeon antigens.