The study aims to determine the prevalence of autism spectrum disorders (ASDs) for children receiving services in Maracaibo County, Venezuela. Children aged 3-9 with diagnosis of any ASD were recruited. We ascertained area, referral process, and definitions of ASD for each patient. A total of 430 children were identified, and 76.5 percent were boys. Prevalences were 1.7 per 1000 for all ASD, 1.1 per 1000 for autism, and 0.6 per 1000 for PDD-NOS and Asperger syndrome combined. These prevalences are lower than current reports in the literature. Differences in case-finding methods, diagnostic criteria, and lack of awareness in the general population may have influenced the number of cases identified. An ASD prevalence of 1.7 per 1000 should alert the health and education authorities to the need to reassess the services available for children with these disorders and their families. (Contains 1 figure and 4 tables.)