Results of Chiari's pelvic osteotomy in Legg-Calvé-Perthes disease were analyzed in 37 hips of 36 patients. The mean age at surgery was nine years. The results were assessed according to both the quality of sphericity and containment of the femoral head. The results were satisfactory in 26 hips (70%), acceptable in 10 hips (27%), and poor in only one hip (3%). In cases where preoperative arthrography revealed a saddle-shaped distortion of the protruding and flattened epiphysis, the results were less satisfactory. The authors conclude that Chiari's osteotomy is needed where other kinds of containment cannot be expected to be successful. The indications are smooth flattenings of severely protruding epiphyses in patients aged seven years or more, and severe epiphyseal protrusions without flattening in patients 10 years or older.