The aim of the study was to analyze the differences in the activity of beta-glucuronidase and beta-glucosidase in stool specimens of children with Inflammatory Bowel Diseases (IBD) and healthy subjects. The disease activity was determined according to the PCDAI scale (Crohn disease) and Truelove-Witts scale (Ulcerative colitis). Enzyme activity was determined by spectrophotometry. There was a correlation between the level of beta - glucosidase activity in stool and patient's age in the group of healthy controls, but not in the IBD group. beta-glucosidase activity in IBD and healthy subjects stool specimens did not differ significantly. The activity of beta-glucuronidase in children with IBD was two times lower than in the healthy group and was correlated with age in children with IBD, but not in the group of healthy ones.