Introduction: Frailty syndrome occurs more frequently in patients with diabetes than in the general population. The reasons for this more frequent occurrence and the interdependence of the two conditions are not well understood. To date, there is no fully effective method for the diagnosis, prevention, and monitoring of frailty syndrome. This study aimed to assess the degree of metabolic control of diabetes in patients with frailty syndrome and to determine the impact of frailty on the course of diabetes using a retrospective analysis. Materials and Methods: A total of 103 individuals aged 60+ with diabetes were studied. The study population included 65 women (63.1%) and 38 men (36.9%). The mean age was 72.96 years (SD 7.55). The study was conducted in the practice of a general practitioner in Wielkopolska in 2018–2019. The research instrument was the authors’ original medical history questionnaire. The questions of the questionnaire were related to age, education, and sociodemographic situation of the respondents, as well as their dietary habits, health status, and use of stimulants. Other instruments used were: the Mini-Mental State Examination (MMSE), Lawton Scale (IADL—Instrumental Activities of Daily Living), Katz Scale (ADL—Activities of Daily Living), Geriatric Depression Rating Scale (GDS), and SHARE-FI scale (Survey of Health, Aging, and Retirement in Europe). Anthropometric and biochemical tests were performed. Results: In the study, frailty syndrome was diagnosed using the SHARE-FI scale in 26 individuals (25%): 32 (31.1%) were pre-frailty and 45 (43.7%) represented a non-frailty group. Statistical analysis revealed that elevated HbA1c levels were associated with a statistically significant risk of developing frailty syndrome (p = 0.048). In addition, the co-occurrence of diabetes and frailty syndrome was found to be a risk factor for loss of functional capacity or limitation in older adults (p = 0.00) and was associated with the risk of developing depression (p < 0.001) and cognitive impairment (p < 0.001). Conclusions: Concerning metabolic control of diabetes, higher HbA1c levels in the elderly are a predictive factor for the development of frailty syndrome. No statistical significance was found for the other parameters of metabolic control in diabetes. People with frailty syndrome scored significantly higher on the Geriatric Depression Rating Scale and lower on the MMSE cognitive rating scale than the comparison group. This suggests that frailty is a predictive factor for depression and cognitive impairment. Patients with frailty and diabetes have significantly lower scores on the Basic Activities of Daily Living Rating Scale and the Complex Activities of Daily Living Rating Scale, which are associated with loss or limitation of functioning. Frailty syndrome is a predictive factor for loss of functional capacity in the elderly.