Rotavirus infection among paediatric patients in Tralee general hospital was monitored over 4 years (1994 - 1998). A total of 2,319 specimens from gastroenteritis patients less than 7 years old were tested by latex agglutination assay, of which 203 (8.75%) were deemed positive. An inverse correlation was observed between age and susceptibility to infection, with the very young (under 2 years) most frequently infected. The virus was almost equally distributed among males (53%) and females (47%) testing positive for rotavirus. A distinctive early Spring peak of infection was evident annually, although the largest peak was identified in December 1997. This correlated with a significant change in circulating genotype as determined by RT-PCR based genotyping analysis of 45 rotavirus samples. In 1997, rotavirus accounted for 64% of all identified paediatric enteric agents at Tralee General for which an infectious agent could be identified. The average hospital stay was 3.2 days, and the direct hospital costs for rotavirus associated gastroenteritis was estimated at pounds sterling 31,232 per annum.