Aims and objectives To investigate attitudes of Irish dental practitioners, cardiologists and patients with cardiac lesions to the new NICE guideline for antibiotic prophylaxis against infective endocarditis and to determine the implications of this guideline for dental practice in Ireland. Methods Individually tailored anonymous postal questionnaires were sent to 500 dental practitioners, 54 cardiologists and 50 patients with a history of antibiotic prophylaxis usage before dental treatment. Results Two hundred and ninety questionnaires were returned from dental practitioners (a response rate of 58%), 20 questionnaires were returned from cardiologists (a response rate of 37%) and 34 questionnaires were returned from patients (a response rate of 68%). Two thirds of patients surveyed would be concerned about the possible cessation of antibiotic prophylaxis before dental treatment and would require either verbal or written confirmation from a cardiologist. Among the dental practitioners surveyed a significant majority were not willing to implement the NICE guideline without further information from the patient general medical practitioner, cardiologist or an official Irish body. Conclusion To enable patient re-education regarding antibiotic prophylaxis, dental practitioners must keep abreast of changes to current guidelines and understand the rationale driving these changes. Difficulties arise for dental practitioners when there is no national statutory body endorsing such guidelines, particularly now that the guidelines in relation to antibiotic prophylaxis in dentistry are so different.