This study evaluated the body image perception in children with type 1 diabetes in order to identify symptoms of disordered eating behaviours early. Children with type 1 diabetes and controls showed underestimation and dissatisfaction with body size. The patients, especially girls, were more accurate in their perception of body size than the control group. The study sheds light on some of the underlying factors that may contribute to the development of disordered eating behaviours in adolescence. The causes of the differences of perception of body size are discussed.