During a period of one year 227 children aged form three days to two years were hospitalized for acute diarrhoea syndrome. In 111 cases (48.9%) the presence of HRV was observed in the faeces (group I). In 116 children (51.1%) no presence was shown of HRV in the faeces (group II). An analysis was done of the significance of differences between the observed clinical sign and abnormalities in laboratory tests in both analyzed groups. It was shown that the general condition of the children in group I was statistically more frequently moderately severe and severe (58.6% and 23.4%) than in group II. Major dehydration over 5% was found in 53.5% of cases in group I, and in 23.4% it was equal to 10% body weight. Body temperature ranged about 38 degrees C in 49.6% of children in group I while in group II in 56.9% it did not exceed 38 degrees C. Vomiting was observed very often (78.4% in group I in comparison to 35.3% in group II), especially preceding the appearance of watery faeces with mucus. The HRV diarrhoea was accompanied significantly more frequently by pharyngitis and rhinitis. Among the results of laboratory investigations of interest was greater tendency of children in group I for hypokalemia and metabolic acidosis and the white blood cell count of below 10,000, observed in 77.5% of patients.