The study characterizes the use of psychoactive medications among children and youth with autism-spectrum disorders over the course of a calendar year. Eighty-three percent of the sample had at least one drug claim during the year. Prescribed drugs came from 125 different therapeutic classes. The seven most frequently prescribed classes of psychoactive drugs were antidepressants, stimulants, tranquilizers/antipsychotics, anticonvulsants, hypotensive agents, anxiolytic/sedative/hypnotics, and benzodiazepines. The data on other relevant diagnoses indicate that children and youth are frequently treated with medication under an autism-spectrum diagnosis, even though the target symptoms may be commonly associated with other mental disorders. Age data indicate that about 70% of children with autism-spectrum disorders age 8 yr and up receive some form of psychoactive medication in a given year.