OBJECTIVE Recent studies have shown that gut microbiota is associated with immunomodulation in transplant recipients, but the composition and function of gut microbiota in renal transplant recipients have not been understood. METHODS We analyzed the composition and function of gut microbiota in the fecal samples from 16 renal transplant (RT) recipients by deep sequencing of the 16S rRNA V3 variable region. The gut microbiota of RT recipients was compared to that of 84 patients with chronic kidney disease (CKD) and 53 healthy subjects. RESULTS The overall microbial structure of RT recipients was similar to that of CKD. The abundance of Firmicutes, Lachnospiraceae, Ruminococcaceae and Faecalibacterium was decreased and that of Bacteroidetes, Proteobacteria, Clostridiales, and Enterobacteriaceae was increased significantly in RT recipients and CKD patients compared with the healthy control subjects. Functional comparison revealed significantly enhanced carbohydrate metabolism and decreased metabolism of cofactors, vitamins, cell motility and genetic information processing in RT recipients and CKD patients. RT recipients and CKD patients also showed slight differences in that the abundance of Proteobacteria and Enterobacteriaceae and the pathways involving transport system members and carbohydrate metabolism were much greater in the former. We found that several beneficial genera in the Lachnospiraceae and Veillonellaceae were negatively correlated with such clinical markers as serum creatinine and blood urea nitrogen. CONCLUSIONS Our results suggested that alterations in the composition and function of gut microbiota are significantly correlated with the clinical conditions of in RT recipients, and future prospective studies of these correlations may provide evidence for predicting the clinical outcomes of RT recipients.