Aripiprazole is an atypical antipsychotic with a novel pharmacologic profile of potent partial agonism at D2 dopamine and 5HT1A serotonin receptors and antagonism at 5HT2A and 5HT2C serotonin receptors. Aripiprazole shows rapid efficacy in acute bipolar mania. Four 3-week studies have shown significantly greater symptom improvement than placebo; a recent study showed an onset of significance as early as Day 2. Aripiprazole also demonstrates sustained efficacy, providing maintenance of effect in two recent 12-week studies, each including a control arm (haloperidol or lithium). Adjunctive aripiprazole provides significant clinical benefits when used with lithium/valproate in patients with bipolar disorder who had an incomplete response to lithium/valproate alone. Aripiprazole was superior to placebo in preventing a new mood episode in a double-blind, placebo-controlled, 26-week study. Additionally, aripiprazole-treated patients had significantly fewer relapses than placebo-treated patients. Patients who completed the 26-week phase continued in a 74-week, double-blind extension (providing a total of 100 weeks of double-blind treatment), during which aripiprazole continued to delay the time to relapse. Aripiprazole demonstrates a good efficacy and tolerability profile in bipolar mania.