Childhood myelofibrosis (Mf) is rare with variable outcome reported in the literature. We present clinical and investigate details of three children who presented with idiopathic Mf in early childhood. Two of these children were identical twins and have been haematologically stable over the past 7 years since their diagnosis. The third patient underwent an allogeneic bone marrow transplant (BMT) procedure as her clinical status was deteriorating. She remains engrafted at 13 months post BMT. None of the children had hepatosplenomegaly although extramedullary haemopoiesis was demonstrated on 52Fe studies in two patients. Circulating progenitors in these patients were increased in the face of reduced marrow precursors. The aetiology of childhood Mf is unclear and its natural history seems different from the adult disease. Allogeneic BMT can be an option for definitive treatment.