Problem behaviors like self-injury, aggression, or disruption will likely require intervention at some point in the life of a person diagnosed with autism. Behavioral intervention has been proven to be effective for addressing these problems, especially when a functional assessment is conducted. Comprehensive treatment for problem behavior is, however, often fractured across studies, resulting in a dearth of studies that show socially validated improvements in these problem behaviors or illustrate the assessment and treatment process from start to finish. In this article, researchers describe an effective, comprehensive, and parent-validated functional assessment and treatment process for the severe problem behaviors of 3 children with autism. After an 8- to 14-week outpatient clinic consultation, no problem behavior was observed at the clinic and in the home. Furthermore, behavior that did not occur during baseline (e.g., functional communication, delay and denial tolerance, and compliance with instructions) occurred with regularity.