In June 1999, a cluster of patients with viral hemorrhagic fever were reported in central provinces of Iran. Similar cases were subsequently verified in other parts of Iran. During June 1999 to February 2004, a total of 255 patients were recorded in Southeast of Iran. The epidemiological features, clinical manifestations, treatment and outcome will be discussed. (c) 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved.