The purpose of this retrospective study is to determine whether frailty is predictive of 30-day readmission in adults 50 years of age and older who were admitted with a psychiatric diagnosis to a behavioral health hospital, 2013-2017. A total of 1,063 patients were included. A 26-item frailty risk score (FRS-26-ICD10) was constructed from electronic health record (EHR) data. There were 114 readmissions.Cox regression modeling for demographic characteristics, emergent admission, comorbidity, and FRS-26-ICD determined prediction of time to readmission was modest (iAUC=0.671; the FRS-26-ICD was a significant predictor of readmission alone and in models with demographics and emergent admission; however, only the ECI was significantly related to hazard of readmission adjusting for other factors (adj.HR = 1.26, 95% CI=(1.17, 1.37), p<0.001) while FRS-26-ICD became non-significant. Frailty is a relevant syndrome in behavioral health that should be further studied in risk prediction and incorporated into care planning to prevent readmissions.