A 45-year-old woman from Mendoza, Argentina, was severely bitten by a dog that died 4 days later. Before death, the dog was nervous, aggressive, and had occasional seizures. Ten days after the woman had been bitten, rabies vaccine treatment was begun: 14 daily doses of suckling mouse brain vaccine followed by 2 booster doses. Twenty-one days after the biting episode, she developed a cerebellar striatal syndrome, which persisted throughout several months, and severe encephalitic symptoms, which persisted for 75 days. After 13 months, recovery was nearly complete. The patient's serum and cerebrospinal fluid contained rabies-neutralizing antibodies reaching maximum titers of 1:640 000 and 1:160 000, respectively. Titers of this magnitude have never been previously recorded after suckling mouse brain vaccine treatment. This phenomenon, together with the epidemiologic, clinical, and laboratory data presented, supports the conclusion of a nonfatal case of rabies in man.