Fewer subjects return to work after acute myocardial infarction or a cardiac surgical procedure than one would expect from the results of their medical examinations and cardiac tests. To decide whether a patient is able to return to work, one has to assess his individual prognosis and measure his maximal physical working capacity without cardiac dysfunction. Psychological and socioeconomic aspects have also to be considered. Recommendations are presented for practical procedure in assessing the ability of a patient to return to work.