Resumo OBJECTIVES: To evaluate dentists' knowledge regarding the prevention of infective endocarditis in Saudi Arabia and their implementation of the 2007 American Heart Association guidelines. METHODS: In this cross-sectional study, in March 2014, 801 dentists who practice in different regions of Saudi Arabia completed a questionnaire regarding the need for antibiotic prophylaxis for specific cardiac conditions and specific dental procedures, prophylaxis regimens in adults and children, and recommendations for patients on chronic antibiotics, and in dental emergencies. The data were analyzed using one-way analyses of variance (ANOVAs) and independent t-tests, and a p-value less than 0.05 was considered statistically significant. RESULTS: The total knowledge level regarding antibiotic prophylaxis among all participants was 52.2%, with a significant difference between dentists who graduated before and after 2007. Comparing the level of knowledge among different dental specialists, surgeons and periodontists had the highest level of knowledge regarding the use of antibiotic prophylaxis. Amoxicillin was prescribed as the drug of choice by 63.9% of the participants. CONCLUSION: This study emphasized the need for continuous education and for formal inclusion of the guidelines in the students' curriculum, as well as for strategic placement of the guidelines in locations throughout dental clinics.