The aim of this study was to determine, in children with different levels of myelomeningocele (MMC), the gait pattern and energy cost of walking with and without ankle-foot orthoses (AFOs). We found that each MMC level was characterised by recognisable gait patterns and that the abnormalities closely reflected the muscle deficits present. Furthermore, the study also introduces new indices for evaluating the energy cost of locomotion and demonstrates that the energy required for walking is increased in children with MMC compared with non disabled children. With respect to barefoot conditions, the use of AFOs leads to an improvement in gait and reduced energy consumption.