In the present study, we wished to explore physical activity in middle-aged patients 6 months after a myocardial infarction and to compare the patients’ self-reported activity level with pedometric measures of footsteps/day. The sample comprised 89 patients with myocardial infarction, aged ≤ 65 years. The self-report question showed that < 40% of the patients were engaged in at least 30 min of physical activity every day. The pedometric physical activity data showed a daily mean number of steps of 6719. The self-report question was correlated with the pedometric registration data. Among myocardial infarction patients, physical activity 6 months after the acute heart attack was insufficient in the majority of patients, both when evaluated with a self-report question and when evaluated with a pedometer. Efforts to increase physical activity after myocardial infarction are warranted.