The incidence of inflammatory bowel disease in children in western countries may be rising. Since there is no prospective national data on the incidence of inflammatory bowel disease in the UK and Republic of Ireland (ROI), we undertook a prospective survey to determine this incidence. The incidence during 1998 and 1999 was 5.2/100,000 per year in children aged younger than 16 years. Those from an Asian background were over-represented and more likely to have ulcerative colitis.