There are indications that the severity of clinical manifestations of chronic heart failure (CHF) is related to the age of patients, with older age groups characterized by a more severe course of CHF and more significant pathological changes in instrumental and laboratory parameters. In view of the above, the aim of the present study was to compare NT-proBNP level, other basic parameters of left ventricular myocardial contractility and the results of 6-min walk test, in CHF patients of different age. We investigated these parameters by dividing the total number of subjects into subgroups of young (18-44 years), middle-aged (45-59 years) and elderly (60-74 years) age according to WHO guidelines. There were 111 patients with CHF (82 men and 29 women) aged 20 to 74 years (mean age 60.4±1.25 years). The patients were divided into three subgroups: 1st - young age (21 patients), 2nd - middle age (37 patients) and 3rd - old age (53 patients). Echocardiographic examination, 6-minute walking test, determination of NT-proBNP level in blood plasma were used during the examination. The number of patients with decreased EF (<35%) was significantly lower among young patients, while those with preserved EF was significantly higher among elderly patients. There were more patients with signs of pulmonary hypertension (high systolic pulmonary artery pressure (SPAP)) among elderly patients. The average distance walked during a 6-minute walk was relatively shorter in elderly patients, as well as a greater number of patients with higher (III-IV functional classes (FC)). The number of patients with elevated blood NT-proBNP levels as well as mean NT-proBNP levels were also relatively higher in the older age groups. Thus, the clinical course of CHF is characterized by a more severe course in elderly patients, despite the prevalence of patients with preserved EF, which is confirmed by more frequent occurrence of FC III-IV, clinical-instrumental and laboratory parameters, and is associated, at least partly, with more frequent occurrence of comorbid pathology.