Objective: To explore the association between frailty and medication adherence by modeling medication beliefs (i.e., necessity and concerns) as mediators among community-dwelling older patients. Methods: This cross-sectional study was conducted among 780 Chinese older patients. Frailty, medication adherence and medication beliefs were assessed using the Comprehensive Frailty Assessment Instrument (CFAI), the 4-item Morisky Medication Adherence Scale (MMAS-4) and the Beliefs about Medicines Questionnaire-Specific (BMQ-Specific), respectively. The PROCESS SPSS Macro version 2.16.3, model 4 was used to test the significance of the indirect effects. Results: Frailty was associated with high medication necessity (beta = 0.091, p = 0.011) and high medication concerns (beta = 0.297, p < 0.001). Medication adherence was positively associated with medication necessity (beta = 0.129, p = 0.001), and negatively associated with medication concerns (beta =-0.203, p < 0.001). Medication necessity and medication concerns attenuated the total effect of frailty on medication adherence by-13.6% and 70.3%, respectively Conclusion: High medication concerns among frail older patients inhibit their medication adherence, which cannot be offset by the positive effect of their high medication necessity on medication adherence. Practice implications: Interventions should target medication beliefs among frail older patients, particularly medication concerns, to efficiently improve their medication adherence. (C) 2020 Elsevier B.V. All rights reserved.