A group of 176 former asbestos workers and 76 unexposed controls of similar age were evaluated and compared for concentrations of serum immunoglobulins, α1‐antitrypsin, carcinoembryonic antigen (CEA), pulmonary function, radiographic appearance of the lungs, rales, cellular atypia and ferruginous bodies in sputum, and smoking habits. Test subjects were evaluated as a single group and also according to years of exposure to asbestos. Both test and control populations were independently subjected to parametric and nonparametric correlation analyses. Partial correlations were also determined for both groups after controlling for age, race, sex, and smoking habits. Analysis of variance was used to compare test and control groups.