Congenital deficiencies and developmental deformities of the upper extremity often result in complex deformities that include, to variable degrees, shortening and angulation. Because of the nonweight-bearing status of the upper extremity, these deformities are better tolerated and often of less functional significance than their counterparts in the lower extremity. The need for lengthening therefore is less common in the upper extremity than in the lower extremity. When planning a lengthening procedure to the upper limb, the surgeon must be aware of some specific indications, goals, and complications. In the final analysis, one must weigh the risk of upper limb lengthening against the benefits. In fact, there are many pitfalls, and it is not a surgery to be undertaken lightly. In the hands of experienced specialists, it can achieve excellent results. The potential complication rate is high initially, but tends to diminish with increasing experience. The authors believe that the functional, cosmetic, and psychological benefits of upper limb lengthening outweigh the risk of permanent sequelae and functional impairment in selected patients.