For the diagnosis of coeliac disease (CD) to be made in children and for the prescription of a gluten-free diet, clear histological changes in the small bowel biopsy sample have to be found. Serological testing for antibodies against endomysium and gliadin has only a preliminary significance. In children with strong clinical suspicion of CD, histological investigation of a small bowel biopsy should be performed independently of the results of serological screening (endomysium and gliadin antibodies). In children with less clear clinical suspicion of CD, serological screening may be used to select those who need investigation of small bowel histology. The number of small bowel biopsies that should be performed has been changed. In children < 2 years with clinical symptoms and small bowel villous atrophy, CD is confirmed when symptoms and atrophy significantly improve during gluten-free diet, while small bowel histology significantly deteriorates during gluten challenge. In children > 2 years with clinical symptoms combined with abnormal serology and villous atrophy, CD is confirmed when during gluten-free diet the symptoms disappear and serology improves. In case of family screening, diseases associated with CD or Down's syndrome, CD is confirmed when symptoms (if any), and previous abnormal serology and small bowel histology significantly improve during gluten-free diet.