Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), is a chronic condition characterized by abdominal pain, diarrhoea, bleeding, and malabsorption. The disease is common in young people (children and young adults) yet it is rather rare in children younger than 2 years. A distinct phenotype of early onset IBD (EO-IBD) in infants and small children with severe intractable enterocolitis and greater tendency to develop colonic disease has been described. Recent work has demonstrated that EO-IBD with manifestation in the first months of life can be monogenic, resulting from mutations in interleukin-10 (IL-10) or its receptor and leading to a loss of IL-10 function. Allogeneic haematopoietic stem cell transplantation (HSCT) can be a successful treatment for those patients. We present here a case of a female IL-10R-deficient patient with severe EO-IBD who underwent HSCT.