The vaccination coverage against diphtheria in the adult population of Russia in 2006-2007 was analyzed in different age, professional and social groups and reasons of absent immunization. Vaccination coverage in adults was 95.3%, of them 92.5% were boosted (i.e. completely immunized) and only 7.5% were in process of vaccination. Vaccination coverage was high in the majority of regions. Mean vaccination coverage in adults aged 25-49 ages was 96.2-96.5% whereas in adultsor =50 years it was lower (91.8-94.8%). Mean coverage in groups of high risk for severe diphtheria was 97.7% in professional high-risk groups and somewhat lower in social high-risk groups (94.4%). The lowest vaccination rate was registered in group of migrants (81.7%). In unvaccinated persons from professional groups 33.1% were not vaccinated due to medical contraindications, 22.8%--because of vaccination refusal, and 38.1%--due to non-medical reasons. In social groups these figures were 21.8%, 28.4%, and 49.8% respectively. Reported mean adult vaccination coverage in Russia is confirmed by results of serological studies. Protective titers were detected in 91.3% tested adults. However in the group agedor =50 years rate of protected persons was lower (84-85%).