An increasing incidence of inflammatory bowel diseases in children and adolescents up to 18 years in six districts of northern and central Moravia (districts Olomouc, Přerov, Vsetín, Šumperk, Bruntál and Jeseník) in the years 1990–1999 was recorded. When comparing the periods 1990–1994 and 1995–1999 a rise in the incidence of Crohn’s disease in children under 15 years from 0.11 to 0.91, in adolescents 16–18-year-old from 0 to 3.83 and in all 0–18-year-old patients from 0.09 to 1.47 was found. In the same period the incidence of ulcerative colitis rose in children under 15 years from 0.55 to 1.43, in 16–18-year-old adolescents from 0 to 2.19 and in all 0–18-years-old subjects from 0.44 to 1.58. The incidence of both IBD’s in 1995–1999 in adolescents 16–18-year-old is higher compared to 0–15-year-old children. This age dependent incidence in 1995–1999 is comparable with published results from other European countries.

        Key words: non-speecific inflammations of the bowel – children – adolescents – Crohn’s disease – ulcerative colitis