The prognostic value of repeat transurethral resection of bladder tumor (TURBT) in patients with diagnosed high-risk, non-muscle-invasive bladder cancer (NMIBC) was investigated. We retrospectively reviewed the medical records of patients treated from October 2004 to December 2013 at Seoul National University who underwent repeated TURBT within 2–6 weeks after an initial resection. The study enrolled patients who had been diagnosed with NMIBC at both the initial and repeat TURBT; patients with muscle-invasive tumors on repeat TURBT were excluded. We used stepwise multivariate Cox regression models stratified by study to assess the independent effects of the predictive factors and estimated hazard ratios (HRs) from the Cox models. We investigated a total of 198 patients who were diagnosed with high-risk NMIBC. In logistic regression analyses, number of bladder tumors (2–7: OR, 2.319; 8≤: OR, 3.353; p<0.05), initially high tumor grade (OR, 2.435; p = 0.040), and presence of carcinoma in situ lesion (OR, 3.639; p = 0.017) correlated with residual tumor in the repeated-TURBT specimen. T1 stage in repeated-TURBT significantly correlated with recurrence (HR, 1.837; p = 0.010) and progression (HR, 2.806; p = 0.029) in multivariate analysis. The high grades of tumors in repeated-TURBT also significantly correlated with progression but not recurrence in the multivariate analysis (HR 2.152; p = 0.008). In this study, the pathologic findings in repeated-TURBT correlated with recurrence and progression in high-risk NMIBC. Repeated-TURBT is valuable because it can predict the recurrence and progression of high-risk NMIBC in addition to obtaining accurate pathologic findings.