OBJECTIVE: Our aim was to study the relative impact of physical fitness, physical demands at work, and physical activity during leisure time on ischaemic heart disease (IHD) and all-cause mortality among employed men with pre-existing cardiovascular disease (CVD). METHOD: We carried out a 30-year follow-up of the Copenhagen Male Study of 274 gainfully employed men, aged 40–59 years who had a history of CVD (ie, myocardial infarction, angina pectoris, and intermittent claudication). We estimated physical fitness [maximal oxygen consumption (VOMax)] using the Åstrand cycling test and determined physical work demands and leisure-time physical activity using a self-reported questionnaire. Results Among 274 men with a history of CVD, 93 men died from IHD. Using male employees with a history of CVD and a low level of fitness as the reference group, our Cox analyses – adjusted for age, blood pressure, smoking, alcohol consumption, body mass index, diabetes, hypertension, physical work demands, leisure-time physical activity, and social class – showed a substantially reduced risk for IHD mortality among employees who were intermediately fit [VOMax range 25–36; hazard ratio (HR) 0.54, 95% confidence interval (95% CI) CI 0.32–0.93] and highly fit (VOMax range 37–50; HR 0.28, 95% CI 0.12–0.66). We found a positive, but statistically non-significant association between physical demands at work and all-cause mortality. CONCLUSION: Among gainfully employed men with pre-existing CVD, a high physical fitness was associated with a substantially reduced risk for IHD and all-cause mortality.