Abstract Two patients presenting with previously untreated asthma were found, on investigation, to have Addison's disease, as evidenced by clinical picture, biochemical findings, and, in one case, necropsy. A 15-month history of both weight loss and asthma in one patient and the onset of asthma after an intercurrent infection and a 4-month history of weight loss in the other suggest that an asthmatic tendency had been uncovered by deteriorating adrenal function. Blood-pressure measurements and serum-electrolyte estimations are recommended for patients presenting with asthma (especially when weight loss is reported).