We evaluated the effect of intravesical Bacillus Calmette-Guerin (BCG) and BCG maintenance therapy on the prognosis of patients with T0 after repeat transurethral resection of bladder mass (TURBT). This retrospective analysis involved 427 patients who underwent repeat TURBT within 6 weeks after initial TURBT from 2007 to 2016. Repeat TURBT was performed in patients with high-risk criteria. Patients who achieved T0 after repeat TURBT did or did not receive intravesical BCG therapy. Patients were divided into three groups: non-BCG, BCG induction, and BCG maintenance groups. The study included 106 patients who achieved T0 after repeat TURBT. The median follow-up was 63 months. There were no significant differences in T stage among the three groups. High grade ratio (p = 0.001) and concomitant CIS ratio (p = 0.037) were significantly higher in the BCG maintenance than in the other two groups. The recurrence rates in the non-BCG, BCG induction, and BCG maintenance groups were 46.2%, 28.3%, and 19.2%, respectively (p = 0.043). Recurrence-free survival was significantly higher in the BCG maintenance group than in the BCG induction group (p = 0.032). Progression-free survival was also higher in the BCG maintenance group than in the BCG induction group, but the difference was not significant (p = 0.056). Multivariate Cox regression analysis showed that only intravesical BCG maintenance therapy was significantly associated with recurrence (hazard ratio 0.016, p = 0.016). In high risk NMIBC patients, intravesical BCG maintenance treatment is required even at T0 after repeat TURBT. Intravesical BCG maintenance therapy of patients with T0 after TURBT reduces recurrence.