Aim:The aim of this study was to evaluate the association of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) with acute rejection after kidney transplantation. Material and Methods: A total of 36 adult renal transplant recipients (33 males, 3 females) with a median age of 41 (range, 19-64) years were included in this retrospective study conducted between January 2016 and January 2019. Data on patient demographics and laboratory findings (neutrophil, lymphocyte, platelet, creatinine, eGFR, serum uric acid and C-reactive protein) were recorded. Acute rejection was defined via renal biopsy in accordance with Banff criteria. Results: Acute rejection occurred in 16 (44.4%) patients. NLR (median 3.75 vs. 1.99, p=0.001) and PLR (median 125.59 vs. 99.23, p=0.008) values were significantly higher in the acute rejection group than in the control group. Area under the curve was calculated to be 0.822 for NLR and to be 0.759 for PLR. Cut-off values were determined to be >2.5 (75% sensitivity and 75% specificity) for NLR and to be >108 (81% sensitivity and 65% specificity) for PLR. Univariate analysis revealed a strong correlation of acute rejection both with NLR >2.5 (Odds Ratio (OR)=0.267, 95% Confidence Interval (CI)=0.089-0.803, p=0.019) and PLR >108 (OR=0.231, 95% CI=0.066-0.810, p=0.022). Conclusion:In kidney transplant patients, there is a strong relationship between high NLR and PLR values and the development of acute rejection. As simple, easy-to-access, inexpensive and non-invasive methods, PLR, and particularly NLR, may be potential tests to diagnose posttransplant acute rejection.