We describe the epidemiological trends and spatial distribution of human brucellosis in Italy over 13 years (1998-2010). In the study period 8483 cases were notified in Italy, with a relevant decrease (-89%) from 1998 to 2010. Most cases were notified in southern Italy (Campania, Apulia, Calabria, Sicily). In these regions we observed relevant differences in the risk of brucellosis at province level. Cases were distributed with a seasonal pattern, male patients represented 60% of the cases and no significant differences were observed between age groups. We modelled the underreporting rate that ranged between 2 and 21 (average 12·5). According to our estimates the true number of cases would have ranged from 41 821 to 155 324 providing a far more severe picture of human brucellosis in Italy than the one provided by the surveillance system.