Intravesical administration of bacillus Calmette-Guérin (BCG) following resection of non-muscle-invasive bladder tumor is the current 'gold standard'. However, up to 40% of patients will fail therapy within the first year and response rates to salvage intravesical therapy after appropriate trial of BCG (i.e., after induction and one maintenance course) average 15-20% at 1 year. Radical cystectomy remains the only treatment with proven long-term benefit after BCG failure. Nonetheless, with appropriate selection, certain patients who 'fail' BCG (but have other favorable risk factors, e.g., a long interval between BCG and recurrence) can be managed with intravesical regimens including repeated BCG, BCG plus cytokines and/or intravesical chemotherapy. In this review, optimal risk stratification, appropriate definitions and management of BCG failures are discussed.