An attempt was made to quantify longitudinal morbidity and identify risk factors associated with high rates of skin breakdown in patients with myelomeningocele. Based on annual evaluations, 227 of 524 patients accounted for 468 positive observations including classic decubiti, abrasions, burns, and ammoniacal dermatitis. Forty-two percent (196) of skin breakdown was attributed to excessive pressure; 57% (267) to other causes; and 1% (5) to unknown causes. Prevalence curve revealed a steady rise from infancy to age 10 years, at which point rates varied between 20-25%. Longitudinal morbidity curves of first skin breakdown showed a tendency of lesions over the perineum or gibbus to appear more frequently in the presence of higher paraplegia (generalized Savage or Mantel-Cox, p = 0.05). However, mildly paraplegic and partially insensate patients exhibited relatively higher rates of breakdown over the lower extremities compared to more paraplegic patients. Higher rates of breakdown were associated with other characteristics such as mental retardation, large head size, kyphoscoliosis, and chronic soiling. Data confirm the high prevalence of skin breakdown in patients with myelomeningocele and reflect an overall influence of growth and development.