Adderall XR (SLI381) is the latest addition to the group of psychostimulant formulations, which provides the mixed amphetamine salts contained in Adderall as a single-daily dose formulation. Adderall XR is indicated for the treatment of attention deficit hyperactivity disorder in children and adolescents, with recent US Food and Drug Administration approval for attention deficit hyperactivity disorder in adults. Novel and important aspects of Adderall XR is its 12 h duration of action, relative superior efficacy to nonstimulant atomoxetine in a comparator trial, and significant quality of life impact in children, confirmed by the largest effectiveness trial yet to be performed for any attention deficit hyperactivity disorder therapy. Potentially important benefits of Adderall XR are proven safety and efficacy in adults with attention deficit hyperactivity disorder and positive postmarketing findings in treating oppositional defiant disorder -- the most common comorbidity in children with attention deficit hyperactivity disorder. This review summarizes the important properties of Adderall XR, to include a distinct two-stage delivery system and combination of active ingredients, offering unique advantages. Relevant clinical trials and the newest data from meeting reports are also discussed.