Peculiarities of the course and diagnosis of hemorrhagic fever with renal sуndrome in Udmurt Republic are studied by the analysis of 583 case records of patients treated from 1990 to 1999 in the urban dialysis center of the medicosanitary department of the Izhmach and other hospitals of Izhevsk. This disease on the territory of Udmurtiya is characterized by severity of the course and sometimes warrants dialysis. The analysis of toxic manifestations makes it possible to predict severity of the course of hemorrhagic fever with renal syndrome in preoliguric period and to determine treatment tactics including the use of replacing therapy.