OBJECTIVE: To determine how the decisions of Dutch cardiologists on surgical treatment for aortic stenosis were influenced by the patient's age, cardiac signs and symptoms, and comorbidity; and to identify groups of cardiologists whose responses to these clinical characteristics were similar. DESIGN: A questionnaire was produced asking cardiologists to indicate on a six point scale whether they would advise cardiac surgery for each of 32 case vignettes describing 10 clinical characteristics. SETTING: Nationwide postal survey among all 530 cardiologists in the Netherlands. RESULTS: 52% of the cardiologists responded. There was wide variability in the cardiologists' advice for the individual case vignettes. Six groups of cardiologists explained 60% of the variance. The age of the patient was most important for 41% of the cardiologists; among these, 50% had a high and 50% a low inclination to advise surgery. A further 24% were influenced equally by the patient's age and by the severity of the aortic stenosis and its effect on left ventricular function; among these, 62% had a high and 38% a low inclination to advise surgery. Finally, 23% of the cardiologists were mainly influenced by the left ventricular function and 12% by the aortic valve area. The presence of comorbidity always played a minor role. CONCLUSIONS: There were systematic differences among groups of cardiologists in their inclination to advise aortic valve replacement for elderly patients, as well as in the way their advice was influenced by the patients' characteristics. These results indicate the need for prospective studies to identify the best treatment for elderly patients according to their clinical profile.