Forty-nine patients treated by epiphysial stapling for idiopathic genu valgum are reviewed. The children were aged from eleven to fourteen and a half years. The severity of the condition and subsequent correction were assessed by measuring the inter-malleolar distance. Results show that femoral stapling is the treatment of choice for most patients with inter-malleolar separation of up to 12-5 centimetres. The optimum age for stapling for both boys and girls is eleven and a half years. Stapling of both epiphyses is advised for those patients presenting late, for example, between thirteen and fourteen and a half years, or where the deformity is greater than 12-5 centimetres of separation. Correction rarely takes more than one year, and was cosmetically satisfactory in all cases. The operation is virtually free from complication except for a tendency for the scars to be broad and conspicuous. Stapling has proved to be a safe, effective and predicatable operation for idiopathic genu valgum.