While the association between Type A behaviour pattern and coronary heart disease (CHD) has been abundantly investigated, the question of the specificity of this association remains virtually unexplored. The present study addressed this question by examining, in a sample of 1949 male and female adults, the relationship between JAS Type A measurement and self-reported diseases (i.e. CHD, scarlatina, rheumatoid arthritis, asthma, diseases of the liver, diseases of the gall-bladder, thyroid troubles, tuberculosis, peptic ulcer, renal disease, hypertension and diabetes). Type A subjects were found to report not only more CHD, but also more peptic ulcers, thyroid problems, asthma and rheumatoid arthritis. Globally, more Type A than Type B subjects reported having been ill, and the average number of reported diseases per person was higher among Type As than among Type Bs. These results were obtained in spite of the fact that Type A subjects in this study were markedly younger than Type Bs, and in spite of the empirically based reputation of the former to be symptom deniers rather than symptom reporters. Overall, the data supported the view that Type A behaviour pattern is a general disease-prone condition rather than merely a specific coronary risk factor.