Abstract Objectives The aim of this study was to investigate the role of preoperative Monocyte-to-Lymphocyte ratio (MLR) as a potential predictor of bladder cancer (BC). Methods Clinical data of patients who underwent TURBT at our institution between 2017 and 2021 were collected and retrospectively analysed. MLR was obtained from preoperative blood analyses performed within 1 month from hospital admission. The association of MLR with different clinic-pathological features obtained from histological reports was further analysed. Statistical analysis was performed using the Kruskal Wallis test for non-parametric variables, assuming p<0.05 as statistically significant. Results 510 patients were included in the study (81% males, 19% females), with a mean age of 71.66 ± 11.64 years. Mean MLR was higher in patients with any-type bladder cancer, reporting an MLR of 0.41 ± 0.11 compared to 0.38 ± 0.43 in patients without bladder cancer (p=0.043). In the subsequent comparison among low-grade and high-grade bladder cancer, MLR did not report statistically significant differences, with 0.29 ± 0.12 for low-grade BC and 0.51 ± 0.81 for high-grade BC (p=0.085) Conclusions Our findings reported elevated preoperative MLR should be considered a potential biomarker predicting malignancy for bladder tumours. Furthermore, research are necessary to assess its role in discerning low-grade from high-grade patients.