This study's purpose was to investigate mortality among individuals with autism spectrum disorders (ASD) ascertained during a 1980s statewide autism prevalence study (n = 305) in relation to controls. Twenty-nine of these individuals (9.5 %) died by the time of follow up, representing a hazard rate ratio of 9.9 (95 % CI 5.7-17.2) in relation to population controls. Death certificates identified respiratory, cardiac, and epileptic events as the most common causes of death. The elevated mortality risk associated with ASD in the study cohort appeared related to the presence of comorbid medical conditions and intellectual disability rather than ASD itself suggesting the importance of coordinated medical care for this high risk sub-population of individuals with ASD.