Bipolar disorder (BPD) is debilitating disorder, and patients can experience multiple relapses and subsequent hospitalizations. Since pharmacotherapy is the mainstay of treatment for patients with BPD, investigations on the effects of atypical antipsychotics (AAP) on reducing rehospitalization risk are crucial. The objective of study is to explore predictors of 1-year rehospitalization in patients with bipolar I disorder treated with AAP. A retrospective chart review on inpatients with bipolar I disorder was conducted. All participants were followed up for 1 year, and they were subdivided into three AAP treatment groups (olanzapine, risperidone, and quetiapine group). Kaplan-Meier survival analysis was implemented to detect time to rehospitalization due to any mood episodes within 1 year after discharge. Cox proportional regression model was adopted to find predictors of 1-year hospitalization in patients who experienced rehospitalization. One hundred thirty-eight participants were included in the study, and a 1-year rehospitalization rate was 18.1%. Time to rehospitalization did not differ between three AAP treatment groups. Predictors of rehospitalization due to any episode within 1 year were family history of depression and number of previous admission. Our findings can be conducive to understanding prognosis, and predicting rehospitalization risk in patients with BPD on AAP.