Objective: To report a case of Reiter's syndrome, an uncommon complication after intravesical BCG therapy. The etiology, clinical features, diagnostic difficulties and treatment of this condition are discussed.

Results: A 56-year-old patient with superficial bladder carcinoma developed conjunctivitis, urethritis and arthritis of the right knee and wrist after the fourth BCG instillation. Other pathologies were ruled out by the clinical and laboratory findings (synovial fluid, cultures, HLA B-27, RF, ANA). A progressive clinical improvement was observed when BCG instillation was discontinued and treatment with indomethacin was started.

Conclusions: Reiter's syndrome is an infrequent complication that is not related with the BCG strain utilized. Early diagnosis of this condition improves response to therapy.