Cardiac rehabilitation can be an effective means for the secondary prevention of coronary heart disease, but a majority of eligible individuals fail to attend or drop out prematurely. Little research has examined patients' decisions about attendance. This paper reports a study examining patients' beliefs and decision-making about cardiac rehabilitation attendance. A purposive sample of patients from a mixed urban-rural region of Scotland was studied in 2001 using focus groups. Those who were eligible for a standardized 12-week cardiac rehabilitation programme were compared, with separate focus groups held for individuals with high attendance (>60% attendance; n = 27), high rates of attrition (<60% attendance; n = 9) and non-attendance (0% attendance; n = 8). A total of 44 patients (33 men; 11 women) took part in eight focus groups. Participants from all groups held sophisticated and cohesive frameworks of beliefs that influenced their attendance decisions. These beliefs related to the self, coronary heart disease, cardiac rehabilitation, other attending patients, and health professionals' knowledge base. An enduring embarrassment about group or public exercise also influenced attendance. Those who attended reported increased faith in their bodies, a heightened sense of fitness and a willingness to support new patients who attended. Reassurance to ease exercise embarrassment should be given before and during the early stages of programmes, and this could be provided by existing patients. Strategies to promote inclusion should address the inhibiting factors identified in the study, and should present cardiac rehabilitation as a comprehensive programme of activities likely to be of benefit to the individual irrespective of personal characteristics, such as age, sex or exercise capacity.