Between August 1988 and August 1991, 456 carcasses of captive or sylvatic hares from several areas of northern Italy, and 931 sera taken from adult hares in farms, in hunting and natural reserves and on importation were examined using virological (sandwich enzyme-linked immunosorbent assay [ELISA] and immuno-electron microscopy) and serological (competition ELISA) tests. The epidemiological data presented relate to the incidence of European brown hare syndrome (EBHS) in various provinces of northern Italy, the mortality caused by EBHS and the seasonal frequency of this disease. The endemic character of EBHS in Italy is proved by the large number of samples testing positive for EBHS virus (EBHSV) (47.6%) and by the results of the seroepidemiological survey, in which approximately 95% of samples tested positive for specific anti-EBHSV antibodies, showing varying titres according to the different environmental conditions.