Six cases of osteogenesis imperfecta with femoral deformity treated by Bailey telescopic nailing are discussed. In 4 cases the operation was bilateral. The long-term results show that this nail lengthens without compromising longitudinal growth of the bone, while providing protection from fracture and recurrence of the deformity. Thinning of the diaphyseal cortex was a significant complication in 3 femurs out of 10. Although it is more difficult to apply, the telescopic nail is preferable to traditional nailing because of its better mechanical features which allow for early weightbearing and walking.