Clean, intermittent catheterization was instituted in 38 babies with myelodysplasia who were thought to be at risk for upper urinary tract deterioration because of neurogenic bladder dysfunction. There were 19 patients 2 weeks to 12 months of age, 11 were 1 to 2 years of age, and 8 were older than 2 years. Effectiveness of clean, intermittent catheterization was determined by maintenance of upper urinary tract stability. Upper urinary tracts improved or remained stable in 13 of 16 infants (81%) with reflux and 16 of 18 infants (89%) with detrusor-sphincter dyssynergia. Bacteriuria was present in 16 (42%), with only 2 infants (5%) having a febrile episode; no infant required hospitalization because of urinary tract infections. No further complications were identified in infants who were cleanly and intermittently catheterized. Most families found clean, intermittent catheterization of their infants easy to master and not stressful, and their children adjusted to it at an early age.