Aicardi syndrome is a rare neurodevelopmental disorder characterized by agenesis of the corpus callosum, other developmental brain abnormalities, chorioretinal lacunae, and severe seizures. Current clinical knowledge is derived from small series that focus on these major defects. The authors performed a health survey on a large number of affected children to expand this knowledge and to uncover previously unrecognized features of Aicardi syndrome. Responses received from caregivers of 69 children with Aicardi syndrome met inclusion criteria for data analysis. Ages ranged from 5 months to 32 years (mean, 88 months). All subjects were girls, except for 1 boy with a 47,XXY karyotype. The authors found that the growth rate in Aicardi syndrome slows at age 10 years to below the 5th percentile and that weight gain slows at age 7 years to below the 25th percentile. The median age of survival was estimated at 18.5 (+/-4) years, more favorable than previously reported. The most common complication aside from seizures was gastrointestinal dysfunction, present in >90%. The results from this survey contribute new information on Aicardi syndrome that will benefit clinical management, and collected data will benefit phenotype-driven research toward its underlying cause.