Background <p>At initial diagnosis, approximately three out of four patients with bladder cancer present with non-muscle-invasive disease. Due to the great heterogeneity regarding the risk of progression and recurrence, risk-adapted diagnostics, treatment, and follow-up are necessary.</p> Objective <p>This article provides an overview of the treatment of non-muscle-invasive bladder cancer (NMIBC).</p> Materials and methods <p>European and German guidelines as well as current literature were considered.</p> Results and conclusion <p>While cystoscopy confirms or excludes a&#xa0;bladder tumor, histological confirmation and surgical removal are performed by transurethral resection (TUR-BT). Commercially available tumor markers are not recommended; only urine cytology is suitable for the detection of high-grade urothelial carcinomas. In certain cases, a&#xa0;subsequent resection is performed to exclude residual tumor or muscle invasion. Patients are then classified into one of four risk categories. Depending on the outcome, adjuvant intravesical instillation therapy with mitomycin or Bacillus Calmette–Guerin (BCG) should be administered. The interval and duration of cystoscopy-based follow-up also depend on the risk classification. The definition of BCG failure is complex. The guideline-based recommendation in these cases is radical cystectomy.</p>