Abstract Background The aim of this study was to identify the prevalence of diabetes in a cohort of frail older adults who attended a model 3 hospital and explore the relationship between frailty and diabetes in this cohort. Prognosis and treatment of diabetes can vary greatly in the presence of frailty. Methods A multidisciplinary team provide liaison geriatric input to frail older adults in this hospital. Comprehensive geriatric assessments (CGAs) are carried out on patients identified using a VIP tool or via inpatient consults. These CGAs were reviewed regarding frailty scores, social/falls history, medications and diabetes complications including hypoglycaemia. Results CGAs were reviewed for 213 patients from September to November 2019. Fifty eight patients had a diagnosis of diabetes (27.2%), and all were type 2. The median age was 84. The average Clinical Frailty Scale score was 5.4 indicating mild to moderate frailty. Over two thirds of patients (n = 137) were on more than 5 medications. Seventy-six patients had a history of falls, and 24 (31.5%) of those had diabetes. Twenty-one patients were prescribed either sulphonylureas and/or insulin, and 7 of these were living alone. One patient had a sulphonylurea stopped on admission following CGA. Five patients had a documented history of hypoglycaemia, 2 of these patients were on insulin and 1 was on a sulphonylurea. The median HbA1c was 49 mmol/mol. Fifteen patients had diabetes complications, including 3 with retinopathy and 6 with neuropathy. The median duration of diabetes was 9.5 years. The majority of patients were managed at primary care level (n = 48, 82.75%). Conclusion The management of frail older adults with diabetes is complicated by multimorbidity and increased risk of adverse effects of treatment such as hypoglycaemia. Frailty assessment should be a routine component of a diabetes review for all older adults, and then glycaemic targets and medication choices should be adjusted accordingly.