To understand differences in the gut microbiota between elderly people of urbanized town communities (UTC) and longevity village communities (LVC), we analyzed fecal microbiota collected from individuals living in 2 UTC (Seoul and Chuncheon) and 3 LVC (Gurye, Damyang, and Soonchang) selected on the basis of indices for superlongevity (the ratio of centenarians to the total population) and longevity (the ratio of those aged 85 years or greater to those aged 65 years or greater) in South Korea by 454 pyrosequencing. Taxonomy-based analysis showed that The relative abundance of Firmicutes, Tenericutes, and Actinobacteria was significantly lower in LVC than in UTC. Due to an increase of Firmicutes and a reduction of Bacteroidetes, the ratio of Firmicutes to Bacteroidetes in the gut microbiota was greater in UTC adults than in UTC children or LVC adults. The population levels of Bacteroides, Prevotella, and Lachnospira were significantly higher in LVC than in UTC, but the levels of Dialister, Subdoligranulum, Megamonas, EF401882_g, and AM275436_g were lower in LVC than in UTC. Although most of the species detected in LVC were detected in UTC, some Bacteroides spp. and Faecalibacterium spp. were detected only in LVC. Among Bacteroides spp., ACWH_s, EF403317_s, and EF403722_s were detected in children and LVC samples only but FJ363527_s, 4P000677_s, and 4P000015_s were detected in UTC samples. EF402172_s and EF404388_s, members of Faecalibacterium spp., which are known to have anti-inflammatory properties, were detected in LVC and children only (>3.9% of total sequence). In addition, the fecal lipopolysaccharides (LPS) content was significantly higher in UTC than in LVC. These findings suggest that maintaining gut microbiota, including Faecalibacterium spp. EF402172_s and EF404388_s, as well as low LPS levels may play an important role in preserving residents' health in LVC.