Introduction. The treatment requirements for high-grade Ta, T1 and T2 bladder cancers differ considerably, thus a correct disease staging is extremely important. The disease staging is often underestimated during primary resection. Upon the histological assessment of T1 bladder cancer, the probability of detecting a muscle-invasive bladder cancer after a secondary resection ranges between 1.3% to 25% and it might increase up to 45% in absence of detrusor muscle fragments at first morphopathological examination. Secondary bladder resection might enhance a relapse-free patient survival, improve BCG treatment outcomes and yield significant prognostic data. Aim of the study. To evaluate secondary transurethral resections of the bladder tumors in order to assess the treatment outcomes. Materials and methods.. Over the January 2018 - August 2019 period, 54 patients underwent a secondary transurethral resection at the Urology Clinic of "N. Testemitanu" SUMPh. The data analysis of the performed interventions, histopathological examination, disease staging and dynamic assessment of the patients was carried out. Results. The histopathological examination identified detrusor muscle after a primary resection in 72% cases. The secondary resection revealed residual tumors in 28% patients with Ta stage and in 35% patients with T1 stage. 68% of residual tumors were detected within the initial resection area. The progression and staging of the pathology were found in 7% (from Ta to T1) and in 11% (from T1 to T2) cases. Conclusions. Residual tumors commonly occur following a transurethral resection of highrisk non-muscle invasive bladder cancers. The secondary resection procedure helps in diagnosing residual tumors and may improve the treatment outcomes, which have been initially assessed as T1 stage.