We evaluated the residual deformity and late treatment of thirty-four hips of thirty-one children who had had septic arthritis when they were less than one year old. The hips were classified into four groups on the basis of radiographic changes. Type-I deformity (five hips) involved transient ischemia of the epiphysis, with or without mild coxa magna, and these hips did not need reconstruction. Type-II deformity (eleven hips) included deformity of the epiphysis, physis, and metaphysis, and these hips needed an operation to prevent subluxation; the goals of the operation included improvement in acetabular coverage, improvement in abductor efficiency by epiphyseodesis or transfer of the greater trochanter, and equalization of limb-length discrepancy by epiphyseodesis of the contralateral limb. Type-III deformity (five hips) involved malalignment of the femoral neck, with extreme anteversion or retroversion or with a pseudarthrosis of the femoral neck that necessitated a realignment osteotomy of the proximal part of the femur or bone-grafting of the pseudarthrosis. Type-IV deformity (thirteen hips) included destruction of the femoral head and neck, with persistence of only a remnant of the medial base of the femoral neck. In the hips that had a Type-IV deformity, the complex clinical problems, which included severe limb-length discrepancy and incompetent articulation of the hip, necessitated operations such as Pemberton osteotomy, trochanteric arthroplasty, arthrodesis, epiphyseodesis of the contralateral limb, and lengthening of the ipsilateral tibia. The functional result was satisfactory in all five hips that had a Type-I deformity, in seven of eleven that had a Type-II deformity, in three of four that had a Type-III deformity, and in only four of thirteen that had a Type-IV deformity.