This research was undertaken to demonstrate the usefulness of a theoretical model for explaining differences in the life satisfaction of persons with different chronic diseases. Through stepwise multiple regression, an assessment was made of the effects of social activity, perceived health, health locus-of control and degree of disability on the life satisfaction of 51 persons with coronary artery disease (CAD) and 32 persons with chronic obstructive pulmonary disease (COPD). Findings were as follows: (1) COPD patients were significantly less satisfied, less socially active and more disabled, and they perceived their health as poorer than did the CAD patients; (2) social activity emerged as the single best predictor of life satisfaction for both groups; (3) the second best predictor was perceived health for the CAD patients and degree of disability for the COPD patients; (4) the four variables accounted for 48 per cent of the variance in life satisfaction for the COPD patients, 12.4 per cent of the CAD patients. It was concluded that predictors of life satisfaction vary with the particular disease, as does the manner in which these factors interact to mitigate or compound the impact of the particular disease. Suggestions are made regarding modification of the theoretical model.