Background: The progression of periodontal disease leads to destruction of the periodontal tissue, allowing bacterial plaque to progress deeper and deeper into the periodontal pocket. More than 500 different bacterial species have been estimated to reside in the subgingival plaque. Hence; the present study was undertaken for assessing the microbial flora in periodontal pockets of non-vital teeth with advanced periodontitis. Materials & Methods: A total of 12 patients with advanced periodontitis were enrolled. Among these 12 patients, a total of 25 non-vital teeth involved with apical periodontitis were assessed. Swabs were obtained from the periodontal pockets with the help of sterilized paper points. Sampling of subgingival pocket plaque was done from the deepest portion of the periodontal pocket. Assessment of the bacterial colonies was done by culture methods. Results: In 60 percent of the teeth, cocci were identified, while in 52 percent of the teeth, rods were identified. In 44 percent of the teeth, spirochetes were identified. Streptococcus and Peptococcus species were found to be present in 40 percent and 44 percent of the teeth. Eubacterium and Actinomyces were found to be present in 28 percent and 24 percent of the teeth. Conclusion: Streptococcus and Peptococcus were the predominant micro-organism in periodontal pockets of non-vital teeth of patients with advanced periodontitis. Key words: periodontal pockets, micro-organisms, Flora