THE INCIDENCE of emphysema is increasing, and with it has come a steady expansion of literature on the subject. To be sure, the increase may be relative, through better diagnosis, or it may be real, due to conditions both known and unknown. There are now more elderly people; industrialization has advanced; smog is on the increase; and smoking (local smog) has reached an all-time high. These factors are, no doubt, contributing to the alarming rise in emphysema. One facet in the etiology of emphysema has not received adequate recognition—the racial incidence. Impressed by the observation that diffuse obstructive emphysema was relatively uncommon in the Negro, we decided to test its validity. Method Included in this evaluation were only those patients with generalized, diffuse, obstructive emphysema. Excluded were patients with emphysema secondary to known underlying pulmonary disorders such as tuberculosis, pneumonoconiosis, bronchiectasis, and sarcoidosis. The patient material considered was gathered from