Introduction Bladder cancer is the most common malignancy involving the urinary system. Recent research tends to emphasize the role of oxidative stress products in the carcinogenesis of bladder cancer. The level of oxidative stress can be measured by assessing the MDA levels. This study aimed to evaluate serum MDA levels in patients with bladder cancer, as well as to determine its potential role as a biomarker in the diagnosis of the disease and progression risk considerations.Methods The study was designed as a cross-sectional study and included 90 patients, divided into three groups with 30 patients each: Ta, T1and T2-T4 group, based on histopathological findings after transurethral resection of the tumor. The control group included 30 healthy volunteers. MDA level was determined using the spectrophotometric method.Results Serum MDA level in patients with bladder cancer [0,86 (0,78-1,05) μmol/L] was significantly higher than the serum MDA level in control group [0,70 (0,69-0,72) μmol/L] (p<0,001). Serum MDA level in Ta group [0,73 (0,70-1,05) μmol/L], T1 group [0,85 (0,80-1,12) μmol/L] and in T2-T4 group [0,91 (0,84-1,04) μmol/L] was significantly higher than the serum MDA level in control group [0,70 (0,69-0,72) μmol/L] (p <0,01). MDA level in T1 and T2-T4 group was significantly higher than the MDA level in Ta group (p<0,01). No significant difference was observed in MDA level between T1 and T2-T4 group (p=NS). A statistically significant positive correlation was found between tumor size and serum MDA level in patients with bladder cancer (rho = 0.254 p <0.01).Conclusion The results of the present study suggest that MDA serum level might play a significant role as a biomarker in the diagnosis of bladder cancer, as well as in the monitoring of its progression.