A case of Hurler's disease is reported in a child with a gibbous deformity of the lumbar vertebrae L1/L2 and a localized diastematomyelia of the spinal cord at L1/L3. The association of an enzyme disorder affecting connective tissue with spinal cord dysraphism has not been reported before, and may be fortuitous. However, as each condition is rare, the occurrence of both gibbous deformity due to Hurler's and diastematomyelia in the same child, makes it unlikely to be a chance association. We suggest that defective neurulation in this case may be related to mesodermal damage associated with mucopolysaccharidosis.A case of Hurler's disease is reported in a child with a gibbous deformity of the lumbar vertebrae L1/L2 and a localized diastematomyelia of the spinal cord at L1/L3. The association of an enzyme disorder affecting connective tissue with spinal cord dysraphism has not been reported before, and may be fortuitous. However, as each condition is rare, the occurrence of both gibbous deformity due to Hurler's and diastematomyelia in the same child, makes it unlikely to be a chance association. We suggest that defective neurulation in this case may be related to mesodermal damage associated with mucopolysaccharidosis.