In 2013, 19 101 cases of hepatitis B virus infection were reported in 28 EU/EEA Member States, a crude rate of 4.4 per 100 000 population. - 2 896 (15.2%) were classified as acute infection and 13 629 (71.4%) were chronic. - The most affected age group for both acute and chronic infections was the group of 25–34-year-olds, accounting for 34.5% of cases; the male-to-female rate ratio was 1.5 to 1. - In 2013, data on transmission were complete for only 21.3% of cases. Among cases with complete information, heterosexual transmission (30.5%), nosocomial transmission (18.9%), injecting drug use... (13.2%) and transmission among men who have sex with men (9.4%) were most commonly reported for acute infections. Mother-to-child transmission was the most common route (43.5%) for chronic cases. - There has been a steady downward trend in the reported rate of acute cases, which is most likely related to the impact of vaccination campaigns. However, geographical and time trends are difficult to interpret because of differences in the application of local case definitions and reporting practices.