From August 2002 to February 2003 25 cases of hepatitis A were notified from one town in Jutland. The first cases were children of three families who returned from an endemic country. The infection spread subsequently in the local community and within households. A case-control study among household index cases showed that hepatitis A was associated with contact to a case in an after-school group (OR 29·6) and with contact to a case household member in a school class or day-care centre group (OR 9·5). From a serosurvey it was estimated that for each notified patient approximately one additional infection has occurred in the households. The infection was imported by children of immigrants, born in Denmark, returning from a visit to friends and relatives in the high-incidence country of origin of their parents and was then propagated through contact between children in after-school groups, schools and their families. Immunoprophylaxis should be given to children prior to visits to friends and relatives in endemic countries and to case contacts.