Real leg length discrepancies may be cosmetically disturbing and lead to gait abnormalities, pelvic obliquity with subsequent lumbar scoliosis as well as functional disturbances of hip, knee and ankle joint. During the growth period even discrepancies of more than 1 cm should be treated by simple conservative means in order to prevent a compensatory lumbar scoliosis. In adults, inequalities up to 2 cm are tolerable. As an alternative to cosmetically often unaccepted shoe lifts for discrepancies of 2 to 6 cm, lengthening and shortening procedures should be considered. The latter involve lower costs and fewer complications. However, reduced final height may be an issue. In cases of an open physis, shortening can be achieved by Blount stapling or percutaneous epiphysiodesis. Considering the minimal number of incisions, simple technique and a low complication rate percutaneous epiphysiodesis is the first choice. The key problem, though, is the correct timing of the procedure. Age, anticipated leg length discrepancy at skeletal maturity, calculated loss of length of the longer leg and growth potential of the shorter leg have to be considered. More complex problems require repeated assessment and documentation of the lengths of both legs in order to find out the individual developmental pattern of the leg length discrepancy, which is primarily associated with the underlying pathology. After skeletal maturity, precise shortening may be achieved by osteotomies with resection of up to 6 cm of bone of the femur and up to 3 cm of the tibia. More shortening is limited by muscle insufficiency, as well as relative increase of soft tissues and risk of compartment syndrome in the lower leg.