Epilepsy is reported to co-occur in individuals with autism spectrum disorder (ASD). Previous studies across the world have found prevalence estimates ranging from 4 to 38%. We examined parent-reported prevalence of co-occurring epilepsy and ASD in the most recent U.S. National Survey of Children's Health, 2011-2012. All analyses accounted for survey weights to account for the complex sampling design. In the overall analytic sample of 85,248 children ages 2-17, there were 1,604 children with ASD (prevalence of 1.8%) and 1,083 children with epilepsy (prevalence of 1.2%). Epilepsy was reported to co-occur in 8.6% of ASD cases. In children with ASD, the co-occurrence of epilepsy was associated with increasing child age, female gender, intellectual disability, speech problems and lower socioeconomic status.