Background: Transurethral resection of the bladder is one of the essential methods in the diagnosis, treatment and management of non-muscularinvasive bladder cancer. The purpose of the procedure is to remove completely all visually detected tumors with a following establishment of a very precise histological diagnosis. Comparison between the results of conventional transurethral endoscopic treatment and the En-bloc resection method using different types of energy sources in the treatment of bladder tumors. Material and methods: A total number of 88 patients underwent endourological interventions. Regarding the distribution, 23 patients had conventional transurethral resection, 22 – En-bloc monopolar resection, 21 – En-bloc bipolar resection and 22 – En-bloc with Thu:YAG laser. Clinical data, intraoperative and postoperative data and also the histopathological examination results were compared. Results: The compared groups were heterogeneous by age, sex, tumor characteristic (size, number, location). No significant differences were observed during the operations, comparing the intraoperative and postoperative complications of the studied groups. The detrusor musculature was detected in 74% of cases after conventional transurethral resection, in 91% of cases of En-bloc monopolar resection, in 95% of cases of En-bloc bipolar resection and in 96% of cases of En-bloc Thu:YAG laser. Conclusions: The En-bloc resection technique of non-muscular-invasive bladder tumors is a safe and effective method comparing with the conventional transurethral resection; it allows more favorable postoperative results and obtaining better quality tumor samples which allow establishing correct diagnosis of the disease.