Six children between 7-16 years of age presented with flail shoulder and elbow caused by poliomyelitis. Shoulder fusion was followed by free-functioning gracilis transplantation to replace the atrophied biceps muscle. The transplanted muscle was reinnervated by either the spinal accessory or phrenic nerve. Follow-up averaged 44 months (range, 56-23 months). All cases developed at least grade 3 power of elbow flexion and were able to place their hands to their mouths. Five out of 6 cases were able to flex their elbow against resistance. One case required tension readjustment, and elbow flexion contracture of 45 degrees developed in another case. On average, the transplanted gracilis started to contract 3 months after transplantation, and muscle power reached grade 2 at 5-6 months and grade 3 at 9-12 months. Muscles supplied by the spinal accessory nerve were earlier to contract and ultimately attained more power than those supplied by the phrenic nerve, probably because of easier rehabilitation. Shoulder fusion and free-functioning gracilis transplantation for biceps replacement provide a solution for restoration of function in children with flail shoulder and elbow, as caused by poliomyelitis. The procedure can be useful in other neuromuscular conditions, such as late-presenting Erb's palsy, especially when no other muscles are available for local transfer.