Aims Using diabetic foot (DF) as an indicator of severe diabetes, we aimed to investigate the cognitive profile of DF patients and the relations between cognitive functioning and both diabetes complications and comorbidities. Methods Dementia-free patients with DF aged 30–90 (n=153) were assessed through medical records and a cognitive battery. Information on diabetes complications and comorbidities was collected via interview; glycated hemoglobin (HbA1c) was tested. Data were analyzed using robust logistic or quantile regression adjusted for potential confounders. Results The mean Mini-Mental Examination (MMSE) score of patients was 24.6 (SD=3.6), and 40% had global cognitive dysfunction (MMSE ≤24). Among elderly patients (aged ≥65), MMSE impairment was related to amputation (OR 3.59, 95% CI 1.07–12.11). Episodic memory impairment was associated with foot amputation (OR 4.13, 95% CI 1.11–15.28) and microvascular complications (OR 9.68, 95% CI 1.67–56.06). Further, elderly patients with HbA1c <7% had increased odds of psychomotor slowness (OR 7.75, 95% CI 1.55–38.73) and abstract reasoning impairment (OR 4.49, 95% CI: 1.15–17.46). However, such significant associations were not shown in adult patients aged <65. Conclusion Amputation, microvascular diseases and glycemic control were associated with impaired global cognitive function and its domains among patients aged ≥65.