Objective: Patients with type 2 diabetes mellitus (T2DM) have high risk of frailty. The clinical frailty scale (CFS) has been used to evaluate clinical frailty. To evaluate the association between CFS and visit-to-visit glycated hemoglobin (HbA1C) variability in T2DM patients. Methods: Patients who were hospitalized with T2DM and received at least three HbA1C tests after discharging from endocrinology department and general practice department during 12-month follow-up were retrospectively enrolled. The patients were divided into the low-HbA1C variability group and the high-HbA1C variability group according to the results of the HbA1C variability score (HVS). The baseline clinical information, including CFS during hospitalization, was collected and compared between the two groups. We performed a propensity score match (PSM) to eliminate the influences of other confounding factors. Results: A total of 370 patients were included in this study. Most baseline demographic, clinical parameters and metabolic parameters were comparable between the two groups except age, baseline HbA1C, albumin, and comorbidities including hypertension and dyslipidemia between the two groups before PSM. All of the relative parameters were comparable after a 1:1 PSM. Uni-variable and multi-variable logistic analysis revealed that higher CFS was associated with higher HbA1C variability and receiver operating characteristic curve showed that CFS had good predictive value in HVS. Conclusion: Higher CFS was associated with higher visit-to-visit HbA1C variability.