ABSTRACT: The gut microbiota represents a source of genetic and metabolic diversity of a complex polymicrobial ecosystem within its host. To investigate age-based variations of the gut microbiota among Shennongjia golden snub-nosed monkeys (Rhinopithecus roxellana hubeiensis), we characterized the microbial species in fecal samples from 18 Shennongjia golden snub-nosed monkeys evenly pooled into 3 aged groups (Group 1, 1-3 years; Group 2, 5-8 years; Group 3, above 12 years) in Shennongjia, Hubei Province, China. Genomic DNA was extracted from fecal samples, and the 16S rRNA gene V4 region was sequenced using the Illumina high-throughput MiSeq platform PE250. A total of 28 microbial phyla were identified in the gut microbiome of these monkeys with the ten most abundant phyla (i.e., Firmicutes, Bacteroidetes, Verrucomicrobia, Spirochaetes, Tenericutes, Proteobacteria, Planctomycetes, Fibrobacteres, Cyanobacteria, and Euryarchaeota). A total of 1,469 (of 16 phyla and 166 genera), 1,381 (of 16 phyla and 157 genera), and 1,931 (of 19 phyla and 190 genera) operational taxonomic units (OTUs) were revealed in Groups 1, 2, and 3, respectively, with Group 3 containing the most diverse groups of OTUs as revealed by the species relative abundance clustering analysis. These results suggest that the gut microbiota in these monkeys maintain a dynamic status, starting from the early developmental stages of life with the species relative abundance increasing with age. This is the first study to comprehensively characterize the gut microbiota and provide valuable information for monitoring the health and nutritional needs of this endangered primate at different ages.