Hospital and laboratory data were analysed in three hospitals to estimate rotavirus disease burden in 1994-96. Community acquired gastroenteritis was diagnosed in 757 children of whom 41% tested positive for rotavirus. A total of 196 children had rotavirus nosocomial infections (39% of all rotavirus community-acquired and nosocomial cases). Infants less than 24 months old and children less than 3 months old comprised 74% and 11.9% of admissions for rotavirus, respectively. Almost 94% of children with rotavirus infection had severe gastroenteritis (score > or =11). The annual rate of rotavirus associated hospitalization in Poland in 1996 was 3.1/1000 children under the age of 60 months and 5.2/1000 infants under 24 months of age. The mean hospital stay was 9.5 d (+/-9.8 d). We estimated that 8918 children under 60 months of age were hospitalized for rotavirus gastroenteritis in 1996; they accounted for 84899 inpatient days. We conclude that rotavirus is a leading aetiological agent of severe gastroenteritis in young children in Poland and that the burden of this infection is significant. Rotavirus vaccine could significantly decrease the hospitalization rate and the financial impact of rotavirus gastroenteritis in Poland.