a b s t r a c tPolymorphisms of genes encoding key factors for the control and activation of inflammatory response and coagulation cascade regulation may play a role in genetic susceptibility to acute myocardial infarction (AMI). This study sought to analyze the effect of TNF À308G/A and pro-thrombin (FII) 20210G/A polymorphisms on the laboratory parameters of young patients affected by AMI. Results indicated that TNF À308A positive genotype frequencies were increased in these patients and that a genetically determined higher production of TNF-a is associated in young subjects to a more severe cardiac damage as depicted by higher levels of troponin, Creatine kinase-MB Isoenzyme (mCK-MB) and a significant increased plasma fibrinogen levels. Similar and probably additive effects on might have a genetically determined increased production of pro-thrombin even if no significant differences in genotype frequencies of pro-thrombin (FII) 20210G/A polymorphisms were observed in this study. All together these results, indicating the relationship among genetically determined TNFa and FII production and increased levels of tissue damage markers of AMI, suggest that a complex genetic background, might be involved in susceptibility to AMI in young men influencing the extension and severity of the disease.