There is a major concern about the increased use of antibiotics in dental practice and the emergence of resistant bacterial strains. In recent years, dentists have reported a shift from narrow-spectrum to broad-spectrum antibiotic prescriptions due to increasing antibiotic resistance. The aims of this study are to investigate the prescribing patterns of the therapeutic and prophylactic use for antibiotics in various dental situations by dental practitioners. The study also specifically investigates the prescribing habits of dental practitioners regarding certain cardiac conditions and related dental procedures in patients predisposed to infective endocarditis. This study utilized a questionnaire which was designed to investigate the antibiotic prescribing patterns by dental practitioners in the Klang Valley region. The returned questionnaires were analyzed using SPSS, to identify compliance to antibiotic guidelines by Malaysia National Clinical Guidelines (MNCG) (2003) and American Heart Association Guidelines (AHAG) (2008). 217 dentists responded to the questionnaire and the responses show that there is a wide variety of antibiotic prescriptions among dentists and there is also misuse of antibiotics in some clinical dental conditions. The results also show that there is a large variation in the antibiotic prescriptions patterns for prophylaxis against infective endocarditis. Furthermore, there is uncertainty as to which cardiac conditions required prophylaxis and for which particular dental procedures. This study concludes that there is a clear need for the development of prescribing guidelines, regular monitoring of antibiotic prescriptions by dental practitioners and educational initiatives to encourage the rational and appropriate use of the antibiotics.