Purpose: The goals of transurethral resection of a bladder tumor (TUR) are to completely resect the lesions and to make a correct diagnosis to adequately stage and treat the patient. Persistent disease after TUR is not uncommon and is why re-TUR is recommended in T1G3 patients. When there is T1 tumor in the re-TUR specimen, very high risks of progression (82%) have been reported. We analyze the risks of recurrence, progression to muscle-invasive disease and cancer-specific mortality (CSM) according to tumor stage at re-TUR in T1G3 patients treated with BCG. Methods: In our retrospective cohort of 2451 T1G3 patients, 934 patients (38.1%) underwent re-TUR. 667 patients had residual disease (71.4%): Ta in 378 (40.5%), T1 in 289 (30.9%) patients. Times to recurrence, progression and CSM in the three groups were estimated using cumulative incidence functions and compared using the Cox regression model. Results: During a median follow-up of 5.2 years, 512 patients recurred. The recurrence rate was significantly higher in patients with a T1 at re-TUR (P <0.001). Progression rates differed according to the pathology at re-TUR, 25.3% in T1, 14.6% in Ta and 14.2% in case of no residual tumor (P <0.001). Similar trends were seen in both patients with and without muscle in the original TUR specimen. Conclusions: Patients with T1G3 tumors and no residual disease or Ta at re-TUR have better recurrence, progression and CSM rates than previously reported, with a CSM rate of 13.1 and a 25.3% progression rate in re-TUR T1 disease. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.