228 persons have been previously vaccinated with inactivated human rabies vaccine Mérieux (HDC). They received three injections of 1 ml by the deep subcutaneous route with a one month interval. The vaccination is completed with a booster of 1 ml one year later. Serum samples for antibody titration are taken just at the time of each injection and also 21 days after the third injection and after the booster. Antibody titration is performed using two different methods: seroneutralization by intracerebral inoculation in mice and focus fluorescent inhibition test. Both methods give similar results. The antibody levels with this vaccine are very high and the average titers are about 1/511 at the day 28 (14,27 I.U./ml), 1/1.558 at the day 56 (59,15 I.U./ml), 1/2.783 at the day 77 (75,09 I.U./ml). In comparison with suckling mouse brain vaccine we obtain titres five times higher with the vaccine HDC (titer 21 days after complete vaccination). The titres are 1/1.109 for HDC vaccine and 1/225 for suckling mouse vaccine. The incidence of second reactions after the different injections is about 27%. They resulted essentially in light pain (21%), redness (17%) and light induration (10%) at the site of the injection during 24 to 48 hours. Fever was observed in less of 1% of cases and no one other general reaction was described.