Introduction To investigate the association between renal function and T lymphocyte subsets and mitochondrial-related parameters in patients with chronic kidney disease (CKD). Methods This retrospective study included patients with CKD between July 2023 and June 2024. Disease stage was assessed based on estimated glomerular filtration rate (eGFR), and patients were classified into CKD stages 1–5 accordingly. Peripheral blood samples were analyzed by flow cytometry to assess T lymphocyte subsets