We report on a female patient attacked by a dog that died 4 days later, who sought treatment 11 days after the accident. A serum vaccination schedule was indicated, to be started immediately with the administration of anti-rabies serum (9 ml, corresponding to 40 IU/Kg body weight) and a series of 10 doses of vaccine applied on consecutive days plus 3 booster doses applied at 10-day intervals, according to the regulations of the Health Secretariat of the State of São Paulo. However, due to an error, 9 vaccine doses were initially applied at 3 different anatomical sites. The error was immediately discovered and it was decided to interrupt treatment for a few days and to restart and complete it later; this was done only 8 days later. Serologic follow-up by the serum-neutralization test in cell culture revealed a fully satisfactory response greatly exceeding WHO recommendations in terms of levels, precocity and duration. The patient continued to be healthy by the 240th day after the accident, when she was observed for the last time before this publication.