Background and Aim: Infective endocarditis is a rare disease resulted in mortality and morbidity in 10-80% of patients. The purpose of present study was to investigate the knowledge of guidelines on antibiotic prophylaxis for bacterial endocarditis in a group of Iranian dentists.

Materials and Methods: This was a descriptive study in which the population under study was 205 who were participated in the 47th international congress of dentistry (Tehran-Spring 2007) and they were chosen by census sampling methods. Nameless questionnaires were designed and were given to the dentists to complete. The t-test, χ² and spearman with the SPSS 13.5 program were used in the data analysis. P<0.05 was considered as the level of significance.

Results: Regarding to the prescribing of prophylactic antibiotic for patients with prosthetic cardiac valves, 94.6% of all answers were correct. Also, the most common procedures in which the prophylaxis antibiotic was distinguished to be necessary were periodontal surgery, scaling, dental extraction and using subgingival cord, respectively. More than half of the dentists (65.8%) had chosen amoxicillin as a prophylactic antibiotic. Mean knowledge score was 38.77±12.4.

Conclusion: Results of the present study showed that the knowledge of dentists about prescribing antibiotics for prevention of bacterial endocarditis is relatively low. It was also found that the level of knowledge decreases by passing time from graduation.