Acute hemolysis as a reaction to rifampicin is extremely rare; case reports number less than 15. We recently evaluated a 65-year-old Cambodian refugee who self-regulated the use of rifampicin and isoniazid for pulmonary tuberculosis. Fifteen minutes after a single discontinuous oral dose, he developed flank pain, chills, rigors, vomiting, diarrhea, fever, and brown turbid urine. Laboratory tests at presentation showed acute intravascular hemolysis. Nonoliguric renal failure ensured, and he was transferred to our institution 2 days later. The patient was group A, Rh (D) positive, P1 negative with a cold autoantibody and cold anti-P1 alloantibody. The direct antiglobulin test was negative at the time of transfer. To evaluate the hemolysis, studies were done to test for rifampicin- or isoniazid-dependent antibodies. Rifampicin-dependent antibodies were detected in the antiglobulin phase with broad spectrum anti-human globulin, monospecific anti-gamma chain, and anti-complement antisera. Agglutination titers did not change after dithiothreitol reduction of the patient's serum. We conclude that this patient developed rifampicin-dependent IgG antibodies with complement-fixing capability. The presence of rifampicin-dependent antibodies should be suspected in a patient with hemolysis and/or renal failure taking rifampicin.