Idiopathic Myelofibrosis (MF) is an extremely rare condition in children. It has a very variable clinical spectrum. Cases of secondary myelofibrosis associated with Vitamin D deficiency and Systemic Lupus Erythematosus have been reported from India .In this case report, the authors describe clinical signs, laboratory findings and histologic features in a 6 month old infant with Idiopathic myelofibrosis.