This paper reviews the clinical pharmacology, efficacy and safety of the novel antipsychotic drug aripiprazole. All published citations regarding aripiprazole were reviewed using a Medline((R)) search (completed for citations through mid-year, 2002). In addition, abstracts from recent scientific meetings presenting data not yet published (nor peer-reviewed) were reviewed. Aripiprazole has a unique mechanism of action as a dopamine D2 partial agonist, serotonin 5-HT(1A) partial agonist and serotonin 5-HT(2A) antagonist. Like other new antipsychotics, aripiprazole has the profile of an atypical agent, with efficacy in the treatment of positive and negative symptoms of psychosis as well as mood symptoms, a low rate of neurological side effects and no significant adverse effect on serum prolactin concentrations. In addition, aripiprazole was not associated with significant weight gain or QTc prolongation in both acute and long-term treatment trials.