OBJECTIVE: To assess health related quality of life (HRQL) and explore its underlying structure in a non-selected population of patients with coronary artery disease (CAD). DESIGN, SETTING AND SUBJECTS: HRQL was estimated by the disease specific Cardiac Health Profile (CHP) questionnaire and the EuroQol-VAS (EQ) in 253 consecutive unselected CAD patients in Södertälje, Stockholm County, Sweden. Explorative factor analysis was used to identify independent dimensions of HRQL. Current angina was ranked according to Canadian Cardiovascular Society Classification (CCS). RESULTS: Four independent principal factors representing perceived cognitive, physical, social and emotional functions underlying the patients' HRQL were found. Identical factors were recognized with an alternate technique. The major factor--explaining 43 % of HRQL--was perceived cognitive function reflecting ability to concentrate, activity drive, memory and problem solving. Cognitive function correlated to EQ but not to CCS. Perceived physical function/general health explained 9% of HRQL and was as expected related both to EQ and CCS. Total CHP scores differed significantly to those of healthy controls. CONCLUSIONS: Perceived cognitive function seems to be a major determinant of HRQL in CAD patients. This, in addition to earlier reports of possible prognostic information of reduced cognitive function, would prompt us to propose that HRQL assessments should include questions aimed to assess cognitive function.