Coeliac disease is a chronic immune-mediated inflammation of the small intestine elicited by the gluten ingestion in genetically susceptible people. In coeliac patients there is higher incidence of other autoimmune disorders like type 1 diabetes or Hashimoto's thyroiditis. The coexistence of coeliac disease and inflammatory bowel disease is rare. The spectrum of presentation of coeliac disease and inflammatory bowel disease may be similar. However, those disorders require various therapeutic approaches. Thus, early recognition of the overlap between coeliac disease and inflammatory bowel disease is crucial to apply appropriate treatment and to prevent possible complications. We report a case of a 6-year-old boy with a delay in physical and psychomotor development, rickets, severe anaemia and bloody diarrhoea. He was diagnosed with coeliac disease and ulcerative disease. The coexistence of both disorders is extremely rare in childhood. However, ulcerative colitis should be considered in coeliac children on restrictive gluten-free diet with persistent diarrhoea or bleeding from lower gastrointestinal tract. Screening for coeliac disease should be considered in children with ulcerative colitis with impaired physical development and lack of remission despite of proper treatment.