Children with meningomyelocele (MMC) frequently have impaired linear growth. A number have associated structural brain defects with resultant GH deficiency (GHD). Reproducible measurements of height or length in MMC patients are often hampered by lower limb contractures, spasticity, and scoliosis. Arm span has been proposed as a more reproducible measure of linear growth. Five MMC children documented to have GHD were treated with recombinant human GH (hGH) for 1-3 yr. Their height, arm span, and growth velocity were compared with 32 children with idiopathic GHD treated similarly with hGH. These measures are compared with normal children by being expressed as standard deviation scores. The results of this study indicate that arm span measurements in GHD MMC patients are almost identical to height measurements in idiopathic GHD patients both before and during hGH therapy. The physical condition of children with MMC makes reproducible longitudinal height measurements difficult. Routine determinations of arm span measurements for children with MMC will assist in recognizing growth failure as well as monitoring treatment results.