Introduction: Atypical antipsychotic drugs are effective in the treatment of bipolar disorder. Studies have shown that atypical antipsychotic drugs are more superior to typical antipsychotic in term of neurocognitive function, negative symptoms and extrapyramidal side effects. Both aripiprazole and quetiapine are atypical antipsychotic drugs that are effective and commonly used in all phases of bipolar disorder treatment. Objective: The aim of this study is to examine and compare the clinical outcomes of aripiprazole and quetiapine in bipolar disorder patients. Method: This was a retrospective cohort study among patients from psychiatric unit, University Malaya Medical Center. Prescription records dated between January 1, 2013 and December 31, 2014 for psychiatric unit were extracted. The data of the subjects with prescription of the two atypical antipsychotic, namely aripiprazole and quetiapine was extracted. The outcome measures were the co-prescription of antihypertensive drugs, antidiabetic drugs and lipid lowering drugs. Results: A total of 58 subjects were recruited, 11 were on aripiprazole and 47 were on quetiapine. Statistical analysis has shown that both aripiprazole and quetiapine do not have any association with compliance to the medication and also follow up. Study also revealed that there is no association between the aripiprazole and quetiapine group with the metabolic side effects that were measured such as systolic or diastolic blood pressure, waist circumference, weight, glucose level and body mass index. Conclusion: This study has shown that both aripiprazole and quetiapine were similar in terms of metabolic side effect, compliance to medications and follow up.