Aim. To assess age and gender characteristics and determine comorbidity, medication, and outcomes in young ambulatory patients with cardiovascular diseases (CVD) within the framework of an ambulatory prospective registry. Material and methods. The study included 3690 patients with hypertension (HTN), coronary artery disease (CAD), heart failure (HF), atrial fibrillation (AF), and combinations thereof, which applied to 3 Ryazan hospitals. Younger CVD patients (criterion 1-the age of 18-49 years, criterion 2-the age of men 18-54 years old and women 18-64 years old) were compared with older representatives. The presence of CVD and comorbidities, medication, and outcomes over 6 year follow-up were analyzed. Results. The age groups of 18-49 years old and ≥50 years old included 347 (9,4%) and 3343 (90,6%) patients, respectively (men-144 (41,5%) and 902 (27,0%), p<0,0001). According to criterion 2, 1369 (37,1%) people were assigned to the group of young CVD patients (men <55 years old-254 (18,6%) and women <65 years old-1115 (81,4%)). The older group included 2321 people (men-792 (34,1%) and women-1529 (65,9%)). In younger CVD patients (by criteria 1 and 2), the proportion of people with CAD, HF, AF, history of myocardial infarction (MI) and/or stroke, diabetes, respiratory and digestive diseases were significantly lower (p<0,001); there was also a lower proportion of people with cardiovascular multimorbidity. According to criterion 1, the proportion of younger people with ≥2 CVDs was 41%; according to criterion 2-62% (p<0,0001). Among patients <50 years of age, AF and stroke occurred in less than 5% of cases; MI was observed only in men. When using criteria 1 and 2 in patients with early CVD development compared with older patients, there was a larger proportion of obesity cases-19,3% and 20,2% vs 13,8% and 10,8%, respectively (p=0,002 and p=0,019) and according to criterion 2, anemia cases-10,2% and 7,1%, respectively (p=0,004). In younger patients, there were higher proportion of adequate medication-70,9% and 68,8% vs 58,5% and 64,6% (p<0,001), lower mortality-9,8% and 10,4% vs 30,8% and 39,7% (p<0,001). However, reinfarction incidence in men <50 years old was higher-22,7% vs 12,4% (p=0,04). Conclusion. In younger CVD patients compared with older patients, in accordance with criteria 1, there was a large proportion of men; in accordance with criteria 1 and 2-lower incidence of CVD and noncardiac diseases, with the exception of obesity and anemia cases (only by criterion 2). Criterion 1 is more applicable for HTN, CAD, and CHF, while criterion 2-for AF, stroke, and myocardial infarction. Younger CVD patients according to both criteria were characterized by a higher proportion of adequate medication, as well as lower mortality, the incidence of non-fatal stroke and CVD hospitalization. Men with MI history at the age of <50 years have higher reinfarction risk. CVD patients at the age of <50 years old are the target group for the prevention of cardiovascular multimorbidity and its progression.