Enterococcus faecalis is a persistent organism that, despite making up a small proportion of the microflora in untreated root canals, plays a significant role in the etiology of persistent periradicular lesions after endodontic treatment. This article provides insight into the various characteristics of E. faecalis, the factors that favor its survival and cause persistent periradicular pathosis, its identification, and current treatment modalities that are effective in eliminating E. faecalis from the root canal system.