While incidence rates of diphtheria steadily declined in Armenia after World War II, reemergence of the disease in 1990 brought about changes in public health practices and identified resource needs. The Armenian Ministry of Health (MOH) routinely collected diphtheria case reports, as a reportable health outcome. Diphtheria incidence rates increased from 0.02/100,000 in 1993 to 1/100,000 (36 cases) in 1994. The distribution of cases showed that the greatest number of illnesses and deaths occurred among persons 5-14 years old, yet incidence rates among persons 1-4 and 5-14 years old were similar (4.4 cases/ and 4.3 cases/100,000, respectively). During 1990-1996, 9 (75%) of 12 cases who died and 18 (21%) of 84 cases who survived had not been vaccinated. The diphtheria epidemic in Armenia was an important, serious, and signal public health event. The Armenian MOH responded by revising immunization practices (1994), improving epidemic control measures (1995), and soliciting international resources (1992-1996).