While the field of applied behavior analysis is not directly involved in the diagnostic process for individuals with autism spectrum disorders (ASD), it is demonstrable that the Diagnostic and Statistical Manual of Mental Disorders , 4th Ed., Text revision, better known as DSM-IV-TR (American Psychiatric Association, 2000) has influenced several aspects of the behavioral treatment of these individuals. This past Spring, the long-awaited DSM-5 (American Psychiatric Association, 2013) was published, to mixed reviews. The structure of the manual was changed; so in particular, were many aspects of the published criteria for a diagnosis of ASD. These changes, including a brief "look-back" at the evolution of ASD diagnostic criteria since first contained in DSM-III will be presented, along with a discussion of the potential impact of the current changes on our field and the treatment of individuals with ASD. Recommendations for future lines of investigation suggested by the new diagnostic criteria will be included, which may ultimately assist Behavior Analysts in improving functional analysis and treatment effectiveness.