The most common endodontic infection which is due to the surface associated growth of microorganism, it brings about the importance of applying the concept of biofilm to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is a prerequisite to understand how the biofilm is formed by root canal bacteria and shows resistance to endodontic treatment measures. Since, bacterial etiology has been root cause for common oral diseases such as periodontal diseases, caries and endodontic infections.The aim of this book was to bring about the understanding of the different types of biofilms, the factors influencing biofilm formation, mechanism of biofilm formation, their roles in periapical and pulpal pathosis, antimicrobial resistance, techniques to identify and manage the biofilm.