Introduction: Aripiprazole is a novel second-generation antipsychotic approved for the treatment of bipolar disorder in adults but there is no systematic data available in pediatric bipolar disorder. Methods: Th is was an 8-week, open-label, proxspective study of aripiprazole 9.4±4.2 mg/day monotherapy to assess the efficacy and tolerability of this compound in treating pediatric bipolar disorder. Assessments included the Young Mania Rating Scale, Clinical Global Impressions-Improvement scale, and Brief Psychiatric Rating Scale. Adverse events were assessed through spontaneous self-reports, vital signs weight monitoring, and laboratory analysis. Results: Fifteen of the 19 bipolar youth (79%) completed the study. Aripiprazole treatment was associated with clinically and statistically significant improvement in mean Young Mania Rating Scale scores (-18.0±6.9, P<.0001). With the important exception of two cases of extrapyramidal symptoms that precipitated dropout, aripiprazole was well tolerated with no statistically significant increase in body weight (1.8±1.7 kg, P=.2). Conclusion: Open-label aripiprazole treatment was beneficial in the treatment of mania in youth with bipolar disorder. Future placebo-controlled, double blind studies are warranted.