This article represents a review of the author's experience with the Wagner lengthening device. Forty patients between 6 and 20 years of age underwent 44 lengthenings of the lower extremity by Wagner's technique (34 femoral and 10 tibial) between February 1977 and January 1999. Shortening was congenital in origin in 24 patients. Lengthening achieved averaged 5.69 cm for the femur and 4.3 cm for the tibia. No complication was observed in 50% of the lengthenings (category I). At least one complication modified the program and necessitated further surgery and general anesthesia in 45.45% of lengthenings (category II). The program was not completed in one patient and complications resulted in a sequela in another patient, representing 4.54% of lengthenings (category III). Twenty-one of the 22 lengthenings without complication were at the femur. Complications were more frequent in patients with a congenital origin. Many complications but no disastrous problems were encountered. Lengthening is better tolerated in children older than 10 years of age. Thirty-nine patients completed their program and were left with less than 2.5 cm discrepancy at the end of growth. The average follow-up was 8.10 years.