We describe a 14-year-old girl with intermediate-type osteopetrosis who presented with a 4.8-cm leg-length discrepancy secondary to premature distal femoral growth plate closure. She had a projected leg-length discrepancy of 7 cm at maturity, which was predicted using Moseley charts. The patient was treated successfully with an epiphysiodesis. Her remaining growth was predicted by Moseley charts. A percutaneous epiphysiodesis can treat leg-length discrepancies in patients with osteopetrosis.