OBJECTIVES: Infl ammatory markers indicate immune system responses. BACKGROUND: We retrospectively explored whether the platelet/lymphocyte ratio (PLR), neutrophil/ lymphocyte ratio (NLR), and red blood cell distribution width (RDW) were predictive of malignant disease. MATERIAL AND METHODS: Between 2019 and 2023, 148 patients diagnosed with malignant and benign renal tumors via imaging or biopsy were included. Of these tumors, 117 were malignant and 31 were benign. Blood samples were taken for calculation of the NLR, PLR, and RDW prior to renal biopsy or operation. RESULTS: The NLR, PLR, and RDW did not differ signifi cantly between patients with malignant and benign renal masses (all p > 0.05). The PLR signifi cantly increased with the T stage of malignant masses (p = 0.011). According to the T stage, the RDW cutoff was 45.7, the sensitivity was 40 %, and the specifi city 82.4 %; the respective values for PLR were 134.9, 70 %, and 70.5 % (p = 0.026 and p = 0.003, respectively). CONCLUSION: The NLR, PLR, and RDW were not predictive in this study because we only included early-stage patients lacking lymph node involvement and the follow-up was short. In patients with renal cell carcinomas, the RDW and PLR increase with the tumor burden and predict poor prognosis (Tab. 5, Fig. 1, Ref. 23). Text i n PDF www.elis.sk KEY WORDS: neutrophil/lymphocyte ratio, platelet/ lymphocyte ratio, renal mass.