Previous studies have yielded some helpful findings about the course of autism into adulthood; yet, longitudinal research using a large population-based sample is needed to better understand this disorder. Proposed is a study of individuals originally identified in the 1980's, now in middle-adulthood. The sample comprises individuals with DSM-III autism and others identified through the 1980's survey that did not reach the DSM-III threshold but would have met DSM-IV criteria for an autism spectrum disorder in childhood. The primary aim is to understand all aspects of current clinical presentations including symptoms of autism, associated features, cognitive status, and comorbid conditions. A second aim focuses on service needs by evaluating current functioning and service use in order to describe service needs and gaps. The third aim is an analysis of childhood variables extracted from the 1980s records and current adult variables. Initial extraction from state vital records databases indicates that data are available on major life events (e.g., mortality, marriage) on 77% of the sample. Based on a pilot study, direct assessment data is anticipated for 75% of living participants (n =203). Analyses of current and historical data may suggest developmental subtypes of ASD with different etiologies. Subtypes may be amenable to certain interventions that could dramatically improve quality of life. In addition to disseminating results about adult functioning and developmental trajectories, this project develop a unique resource for future studies of autism in adulthood that use genetic, imaging, and intervention techniques. The study should lead to additional follow-up in later adulthood.