The authors compare two groups of subjects: patients with bronchial asthma and those with coronary disease, with regard to some social characteristics, abilities and perception of factors which they conceive are important in the etiology of their disease. Data were obtained by means of a questionnaire based on a known calibrated scale. A group of 100 patients with bronchial asthma and a group of 102 patients with coronary disease were examined. The significance of the difference was tested by chi 2, t-test, Wilcoxon's test and multivariate discriminative analysis. The results showed statistically significant differences between the patients with bronchial asthma and those with coronary disease in some social and psychological characteristics and also with regard to perception of potential etiological factors of their disease. However, no difference was found in life style and habits between the coronary and asthmatic patients.