OBJECTIVES: In this study, we evaluated the maintenance-treatment strategies of bipolar I and bipolar II disorders of KMAP-BP 2018. METHODS: The questionnaire used to survey experts for their opinions of medication used for the treatment of bipolar disorder was completed by the review committee consisting of 84 experienced psychiatrists. It is composed of 50 questions, and each question includes various sub-items. The questionnaire for maintenance treatments was composed of overall treatment strategies after acute mood episodes in bipolar I and II disorders, including the choice of antipsychotic and antidepressant drugs, duration of medication, and treatment strategies used to achieve a breakthrough in symptoms. RESULTS: In case of bipolar I disorder, mood stabilizer monotherapy, a combination of mood stabilizer and atypical antipsychotic drugs, and atypical antipsychotic drug monotherapy were the first-line treatments. In maintenance management for bipolar II disorder, combinations of mood stabilizer and mood stabilizer monotherapy or atypical antipsychotic monotherapy were preferred. Atypical antipsychotic drugs were favored as the maintenance treatment for bipolar I and II disorders in KMAP-BP 2018. CONCLUSION: There have been growing bodies of tendency that atypical antipsychotics are more preferred than previously in the KMAP-BP 2014.