The number of hepatitis B carriers in Gothenburg, the second largest city in Sweden, has gradually increased between 1980 and 1990. Altogether 525 chronic carriers (35% females) were found, corresponding to a prevalence of 0.11%. 401 (76%) were immigrants from high or medium prevalence regions, mainly the Middle East and Southeast Asia. 102 were native Swedes (19%). In 1988-90 the immigrants constituted 85% (154/182) of all new cases. 93% (245/264) of the carriers born in 1960-89 were immigrants, whereof 53% (130/245) were HBeAg positive. The increasing number of hepatitis B carriers in Sweden places demands on the public health service to undertake measures to prevent new cases of hepatitis B, as well as to discover and treat chronic liver disease induced by hepatitis B virus.