Haemorrhagic fever with renal syndrome is endemic in parts of Slovenia. Since 1999, in January to April each year, the number of notified cases has generally been low (n=0-6). A high number of cases (n=26) in the first four months of 2012 has been observed, similar to that seen in the same period in 2008 (n=14). Given the increase in the number of cases at the start of 2012, we can expect a high number of cases this year.