Background:T-lymphocyte subsets reflect patients' immune status and are associated with adverse outcomes in various diseases. However, the association between T-lymphocyte subsets and major infection and renal outcome in chronic kidney disease (CKD) patients has not been well-addressed.Methods:Patients diagnosed with stage 3–5 of non-dialysis CKD were recruited, and healthy subjects were selected as the controls. T-lymphocyte subsets (CD3⁺, CD4⁺, CD8⁺) were detected by flow cytometry, and the CD4⁺/CD8⁺T cell ratio was then calculated. Patients were divided into the normal-level group and the low-level group according to the clinical reference value. The primary outcomes were the major infection and renal outcome.Results:A total of 410 CKD patients were enrolled; the average age was 47.25 years. Compared to the healthy controls, the level of CD3⁺, CD4⁺, CD8⁺T cells, and the CD4⁺/CD8⁺T cell ratio were significantly decreased in CKD patients (p< 0.05). During the median follow-up of 2.56 (quartile interval 1.24–3.46) years, major infections occurred in 15.10% of the CKD patients. The incidence of infection was significantly higher in the low-level group of CD3⁺, CD4⁺T cells, and CD4⁺/CD8⁺T cell ratio compared with the normal level groups. Kaplan-Meier analysis showed that the lower level of CD3⁺, CD4⁺T cells, and CD4⁺/CD8⁺T cell ratio is associated with a greater risk of infection. Cox regression analysis further confirmed that low CD3⁺, CD4⁺T cells, and CD4⁺/CD8⁺T cell ratio were independent risk factors of infection in CKD patients. Moreover, during the follow-up, renal events occurred in 37.50% of patients. Kaplan-Meier analysis indicated that low levels of CD3⁺, CD4⁺, and CD8⁺T cells are significantly associated with renal outcome in CKD patients. Cox regression analysis showed that low level of CD3⁺T cells (HR = 2.407, 95% CI: 1.664–3.482,p< 0.001), CD4⁺T cells (HR = 2.397, 95% CI: 1.633–3.518,p< 0.001) and CD8⁺T cells (HR = 2.416, 95% CI: 1.476–3.955,p< 0.001) were independent risk factors for renal outcome after multivariable-adjusted.Conclusion:CKD patients had a defect in T-lymphocyte subpopulation. T-lymphocyte subsets were closely associated with infection and renal outcome in CKD patients. Suggesting T-lymphocyte subsets are independent predictors of infection and renal outcome in CKD patients.