Polymerase chain reaction was used to study the association of polymorphic markers I/D of the angiotensin-converting enzyme gene (ACE) and A1166C of the angiotensin II type 1 receptor gene (AT2R1) with chronic heart failure (CHF) in Russian and Tatar patients that had had myocardial infarction. In Russian patients aged 50 years or younger that had had macrofocal myocardial infarction, the CC genotype of the A1166C polymorphic marker of gene AT2R1 was associated with an increased risk of CHF (OR = 11.36). Genotype DD and allele D of the I/D polymorphic marker of gene ACE were associated with a more severe CHF (functional class III-IV) in Russian patients (OR = 3.50 and 2.06). In Tatar patients, polymorphic markers I/D of gene ACE and A1166C of gene AT2R1 were not associated with CHF.