To assess prognostic significance of residual tumor at repeat transurethral resection (reTUR) in contemporary non-muscle-invasive bladder cancer (NMIBC) patients. Patients were identified retrospectively from eight referral centers in France, Italy and Spain. The cohort included consecutive patients with high or very-high risk NMIBC who underwent reTUR and subsequent adjuvant BCG therapy. A total of 440 high-risk NMIBC patients were screened, 29 (6%) were upstaged ≥ T2 at reTUR and 411 were analyzed (T1 stage: n = 275, 67%). Residual tumor was found in 191 cases (46%). In patients with T1 tumor on initial TURBT, persistent T1 tumor was found in 18% of reTUR (n = 49/275). In patients with high-grade Ta tumor on initial TURBT, T1 tumor was found in 6% of reTUR (n = 9/136). In multivariable logistic regression analysis, we found no statistical association between the use of photodynamic diagnosis (PDD, p = 0.4) or type of resection (conventional vs. en bloc, p = 0.6) and the risk of residual tumor. The estimated 5-yr recurrence and progression-free survival were 56% and 94%, respectively. Residual tumor was significantly associated with a higher risk of recurrence (p < 0.001) but not progression (p = 0.11). Only residual T1 tumor was associated with a higher risk of progression (p < 0.001) with an estimated 5-yr progression-free survival rate of 76%. ReTUR should remain a standard for T1 tumors, irrespective of the use of en bloc resection or PDD and could be safely omitted in high-grade Ta tumors. Persistent T1 tumor at reTUR should not exclude these patients from conservative management, and further studies are needed to explore the benefit of a third resection in this subgroup.