Because of its proven efficacy, intravesical Bacillus Calmette-Guérin (BCG) immunotherapy is an important treatment for nonmuscle invasive bladder cancer at high risk of recurrence or progression. However, approximately 8% of patients have to stop BCG instillation as a result of its complications. Complications induced by BCG therapy can have a variety of clinical manifestations. These adverse reactions may occur in conjunction with BCG instillation or may not develop until months or years after BCG cessation. An essential step in the management complications arising from BCG is early establishment of diagnosis, particularly for distant, disseminated, and obscure infections. Therefore we reviewed the literature on the potential complications after intravesical BCG immunotherapy for bladder cancer and provide an overview on the incidence, diagnosis, and treatment modality of genitourinary and systemic BCG-induced complications.