There have been few reports associating avascular necrosis of bone with Cushing’s disease. Patients with Cushing’s disease and avascular necrosis of the femoral head usually receive total hip arthroplasty. However, hip prosthetic replacement in younger patients has been criticized due to a high incidence of component loosening. We report a case of successful femoral head preservation in non-united femoral neck fracture and head osteonecrosis in a 14-year-old girl with Cushing’s disease (adrenocorticotropic hormone-secreting pituitary adenoma) who developed avascular necrosis of the right femoral head and pathologic fracture of the right femoral neck 2 years after the onset of hypercortisolism. Subtrochanteric valgus osteotomy was performed to preserve the femoral head after successful transsphenoidal surgery to remove pituitary microadenoma. At follow-up 10 years after the osteotomy, the femoral head had revascularized and the femoral neck fracture were united with much improvement of hip function. Dual energy X-ray absorptiometry scan of the right hip showed +0.86 SD from the normal bone densitometry. Aggressive femoral head preservation may be an effective alternative to treat this rare situation in a teenager.