Hepatitis A is a mandatory notifiable disease in Denmark. The number of notified cases of hepatitis A was compiled over a period of 16 years, 1980-1995. A total of 3790 were included in the study. The average incidence was 4.6 per 100,000 population per year, but the number of cases declined slightly through the period. Median age among Danes were 27 years and among immigrants seven years. The male to female ratio was 1.5 among Danes and 1.1 among foreigners. The incidence was highest in the capital area. Two-thirds of the notified persons were infected in Denmark, among whom the source of infection was unknown for half of the cases. The two most important sources of infection were household contracts and i.v. drug abuse. A total of 73 persons were infected in connection with their occupation in Denmark. Workers in day care centres, sewage workers and cleaners may be particularly at risk, although the risk is still low. The relevance of vaccination recommendations for special groups is considered.