Blount disease or idiopathic tibia vara is a developmental deformity of the proximal tibia! medial physis that produces a varus deformity of the knee. It is classified by early or late onset. The etiology is not entirely clear but is presumed to be related to an abnormal compression on the medial aspect of the proximal tibia! physis. Early diagnosis is important for a better prognosis. In general, the later the onset and the greater the progression of the deformity, the increased likelihood of articular changes. Orthotics are recommended as the first type of treatment. If progression occurs or onset is late, surgical intervention may be warranted. The nurse's role ranges from educating the family about the disease to helping them adapt to the varying treatments.