Introduction. The aging of population and increase in the incidence of type 2 diabetes mellitus (DM2) dictate the need to study cognitive functions in elderly and senile people with this nosology. Aim: to study cognitive functions in elderly patients with DM2. Materials and methods: 200 elderly people participated in the study. The first group (the main one) included patients with DM2 (100 people), the second, control group – without DM2 (100 people). All participants of the study collected complaints, anamnesis, bad habits (smoking), anthropometric measurements, the level of glycemia after meals (postprandial glycemia, PPG), assessment of cognitive functions using the Montreal scale (MoCA). Results: in the first group, the overall MoCA score, as well as scores in assessing cognitive areas such as memory, attention, abstraction and delayed reproduction, were significantly lower than in the second (p