We aim to study the characteristics of risk factors and background diseases in elderly and senile patients with acute ischemic stroke (AIS). In-depth analysis included 282 observations of different types of AIS in individuals aged 42–60 years (95 observations), elderly (133 patients aged 60–74 years) and senile (54 patients aged 75–90 years) age. Among people aged 42–60 years, there was a 2-fold predominance of men with AIS (66.2%) as compared with senile aged patients (31.5%). The pattern of prevalence of women with age was established, so if at the age of 42–60 years their percentage with AI was 33.7%, then at the age of 75–90 years - 68.5%. Among men aged 42–60 years and 60–74 years, there was a significant (P < 0.05) prevalence of Atherotrombotic Stoke (AS) (p < 0.05), which was 65.6% and 66.7%, respectively, compared with 21.9% and 31.1% of AS observations in women. Patients aged 42-60 years in the structure of background diseases revealed the prevalence of arterial hypertension (AH) (90.5%), the presence of atherosclerosis (87.4%) of cardiac rhythm and rheumatism (45.3 and 47.4%, respectively), diabetes mellitus (23.2%). There was a significant predominance of atherosclerosis, arterial hypertension, ischemic heart disease, TIA, rheumatism in men (p < 0.05), and diabetes mellitus and heart rhythm disturbances in women (p < 0.05). There was a leveling of gender differences in the structure of background diseases due to an increase in the proportion of atherosclerosis in women (p < 0.05), and diabetes in elderly men (p < 0.05).