Determinants of compliance with a 6-month diet and exercise program were studied among 118 healthy middle-aged men with risk factors for coronary heart disease (CHD). Data were gathered via medical examinations, interviews and questionnaires. Smoking, high levels of hostility, perception of barriers to diet change and low knowledge of risk factors for CHD were linked to poor compliance with increased intake of dietary fiber. Poor compliance with low fat diet was linked with smoking, younger age and not having relatives or friends afflicted with CHD. Poor compliance with the exercise program tended to be associated with younger age and having children at home. Practice implications for health professionals who provide clinical and educational services for middle-aged men with slightly elevated CHD risk factors are discussed.