Aripiprazole is a recently released antipsychotic medication which differs from other atypical antipsychotic agents by its partial agonist activity at postsynaptic D2 receptors. It is administered orally and is distinguished by a long elimination phase half-life relative to other antipsychotic medications. Randomized studies have demonstrated the efficacy of aripiprazole relative to placebo in the treatment of acute relapse of schizophrenia and schizoaffective disorder, maintenance treatment of schizophrenia, and treatment of acute bipolar mania. Aripiprazole is generally well tolerated relative to other antipsychotic medications, although commonly reported side effects include worsening extrapyramidal symptoms and motoric activation similar to akathisia. Further studies and postmarketing data will be helpful in providing additional information about the comparative safety, efficacy and tolerability of aripiprazole.