81 patients were included in the research into study of acute myocardial infarction (AMI) clinical course features in patients with various polymorphism of gene. These patients besides traditional examination, received genetic examination for determination of of NO-synthase gene in intron 4 (eNOS 4a/4b polymorphism) and mutation in position 298 of protein sequence leading to replacement of rest of glutamine acid by asparaginic acid (Glu298Asp). Patients with allele 4a polymorphism of endothelial NO-synthase gene in intron 4 (genotypes 4a/4a and 4a/4b) had low level of high-density lipoprotein cholesterol (HDLC) in comparison with 4b homozygote patients. Inverse association of 4a allele with HDLC did not depend on the AMI therapy character. Besides, it was detected that AMI patients with 4a/4a polymorphism had bronchial asthma and chronic hepatitis more frequently than patients with 4b/4b genotype. AMI patients with 4a allele had early postinfarction angina and gastroesophagoreflux disease. The relation of allele 4a carriage with development of early postinfarction angina depended on presence of bronchial asthma in AMI patients. AMI patients with Glu298Asp polymorphism Asp/Asp genotype did not have significant differences in AMI and concomitant pathology course in comparison with Glu/Glu genotype patients.