Pelvic obliquity caused by leg length discrepancy is a problem facing patients with a wide variety of conditions. It is the degree of discrepancy and the growth pattern of the legs that usually govern treatment decisions, with the cause of the discrepancy having little influence. We analyzed the results recorded in 345 patients with pelvic obliquity caused by leg length inequality operated on between 1969 and 1989. In 146 patients a shortening procedure was done and in 199 patients a lengthening procedure. Biological bone growth stimulation did not prove to be predictable and effective in 65 cases. In 134 patients and 138 segments a distraction procedure was performed. In 26 segments the technique was according to Wagner; in 37 cases the Ilizarov fixator was used and in 75 the Orthofix device. Excellent results were obtained in 65% and good results in 23%; the condition became worse in 12%. Analysis of the results justifies the use of epiphysiodesis, shortening osteotomies and bone lengthening according to the biological principles investigated by Ilizarov in the presence of well-defined indications outlined in this report. Patients with a discrepancy of up to 2-3 cm are treated conservatively by shoe lift. For patients with a leg length inequality of 3-5 cm, epiphysiodesis or shortening osteotomy is still a good indication although lengthening procedures can also be performed. Discrepancies between 5 and 15 cm are treated mainly by lengthening operations. New lengthening techniques such as corticotomy and callus distraction, as well as new external fixation systems like Orthofix and Ilizarov, have made bone lengthening a less risky, easier, and more effective procedure. In a growing child, careful clinical and radiological assessment and repeated analysis of past growth in order to predict future growth can provide an exact plan for effective treatment, which often consists of bone lengthening, combined with shortening procedures on the contralateral side to establish leg length equality even in cases when there is 20 cm difference. Surgical treatment can be especially gratifying when anatomical, cosmetic and functional symmetry is restored and a lifetime of shoe lifts, braces or prostheses can be avoided.