Between 1979 and 1990, 148 newborns with myelodysplasia were followed with serial urodynamic studies and neurological assessment. Of the patients 59 (40%) exhibited changes in neurological status by age 5 years, of whom 28 (19%) showed signs of deterioration. Most changes occurred before age 2 years. A total of 22 children underwent repeat neurosurgical exploration because of a change in urethral sphincter innervation (17), deterioration of function of the lower extremities (3), or changes on computerized tomography or magnetic resonance imaging (2). Postoperative urodynamic evaluation demonstrated improvement in 11 children, stabilization in 9 and further deterioration in 2. The earlier that a change was detected and secondary surgery was performed, the better the outcome. These findings indicate that the neurological lesion in myelodysplasia is a dynamic disease process requiring continuous neurological, orthopedic and urodynamic surveillance. Early identification and prompt neurosurgical reexploration seem to arrest and even reverse the neurological deterioration that takes place in a substantial number of these children.