Purpose <p>International guidelines present discrepancies concerning restaging transurethral resection (TURBT) for high-grade (HG) Ta bladder cancer. Recent studies with heterogeneous inclusion criteria have reported discordant results regarding its benefits. Our study aimed to assess the prognostic impact of restaging TURBT in patients with HG Ta that was fully resected during the initial TURBT.</p> Methods <p>This single-center retrospective study involved patients with HG Ta. Patients with a history of urothelial carcinoma ≥ HG Ta, macroscopically incomplete resection, or the absence of detrusor muscle in the resected tissue were excluded. The decision to perform restaging TURBT was left to the discretion of the operating surgeon. Adjuvant treatment and follow-up were conducted according to established guidelines.</p> Results <p>A total of 181 patients were identified, with 111 included in the survival analysis. Patients who underwent restaging TURBT presented more frequently with multifocal lesions and were more likely to receive adjuvant therapy. Conversely, patients who underwent only TURBT had a higher prevalence of previous low-grade Ta tumors. The median time to restaging TURBT was 49 days. Residual tumors were detected in 36.4%, with 4.6% classified as pT1. Restaging TURBT did not impact RFS. In multivariate analysis, the use of photodynamic diagnosis PDD (HR = 0.3, <i>p</i> = 0.03) and adjuvant therapy (HR = 0.5, <i>p</i> &lt; 0.01) were associated with a reduced risk of recurrence. Restaging TURBT did not significantly influence PFS.</p> Conclusions <p>Restaging TURBT did not affect the risk of recurrence or progression in patients with HG Ta following a complete initial TURBT. These findings are consistent with recent updates in clinical guidelines.</p>