INTRODUCTION: Aripiprazole is approved for the acute and maintenance treatment of manic and mixed episodes associated with bipolar I disorder. The aim of the present work was to review and meta-analyze the findings of all the available randomized double-blind controlled trials (RCTs) on the efficacy of aripiprazole in the treatment of bipolar disorder.MATERIAL AND METHODS: Aripiprazole RCTs were identified with a systematic search of MEDLINE and repositories. Standard meta-analytic techniques were applied.RESULTS: Two thousand three hundred and three patients took part in the aripiprazole acute mania RCTs. At week 3 the pooled aripiprazole vs. placebo effect size was 0.34 and the NNT was 6 for response and 14 for remission. On average, response started at day 3. Suicide rates were negligible for all groups in mania but they were not reported in the acute depression trials. The meta-analysis of acute bipolar depression RCTs revealed a significant difference at week 8 with a weak effect size equal to 0.17. The analysis of maintenance data suggest that the median survival time for the aripiprazole group was not evaluable (very long), while the median survival time for placebo was 118-203 days depending on the clinical subpopulation.DISCUSSION: The current meta-analysis supports the usefulness of aripiprazole during all phases of bipolar illness. Its effect against acute bipolar depression is weak and the efficacy during the maintenance phase is proven only against new manic episodes in patients with an index manic episode who had previously responded to aripiprazole during the acute phase.