BACKGROUND: Time is crucial when an acute myocardial infarction (AMI) occurs, but patients often wait before seeking medical care. AIM: To investigate and compare patients' and relatives' knowledge of AMI, attitudes toward seeking medical care, and intended behaviour if AMI-symptoms occur. METHODS: The present study was a descriptive, multicentre study. Participants were AMI-patients ≤ 75 years (n = 364) and relatives to AMI-patients (n = 319). Questionnaires were used to explore the participants' knowledge of AMI and attitudes toward seeking medical care. RESULTS: Both patients and relatives appeared to act more appropriate to someone else's chest pain than to their own. Patients did not have better knowledge of AMI-symptoms than relatives. Women would more often contact someone else before seeking medical care. A greater percentage of elderly (65-75 years), compared to younger individuals, reported that they would call for an ambulance if chest pain occurred. CONCLUSIONS: There were only minor differences between patients and relatives, regarding both knowledge and attitudes. It seems easier to act correctly as a bystander than as a patient. Therefore, in order to decrease patients' delay time it is important to educate relatives as well as patients on how to respond to symptoms of an AMI.