A 56-year-old man who had previously undergone transurethral resection and intra-arterial chemotherapy for bladder cancer developed irritable bladder, bilateral conjunctivitis and arthritis including the knees, ankles and sacroiliac joints after starting intravesical Calmette-Guerin bacillus (BCG) immunotherapy. These symptoms were in agreement with the features of Reiter syndrome. One month after cessation of the intravesical BCG immunotherapy and initiation of the treatment with a non-steroidal anti-inflammatory drug (NSAID), he was not complaining of symptoms. Reiter syndrome is an uncommon complication after intravesical BCG immunotherapy. Nevertheless, since the prolonged arthritis has a possibility to cause joint deformity, we must pay serious attention to this side effect.