Thromboembolism is a multifactorial disease affecting genetically predisposed individuals when exposed to circumstantial risk factors. Among these factors, moderate hyperhomocysteinemia (MHH) resulting from methylenetetrahydrofolate reductase (MTHFR) deficiency has been identified as risk factor for venous thrombosis. A main genetic defect related to MHH is a C to T substitution at nucleotide 677 of the 5, 10 MTHFR gene.The prevalence of the C677T MTHFR gene mutation is not increased in patients with DVT, indicating that this mutation itself is not a genetic factor for DVT. We have demonstrated that the multiplicity of risk factors revealed a significant difference in DVT patients compared to controls with a highly significant negative correlation between the number of risk factors and the duration between the two thrombotic episodes. Also, we have noted a significant difference regarding the multiplicity of risk factors in MTHFR mutated DVT patients compared to MTHFR mutated controls, indicating that inherited thrombophilia is a multigene disorder, where the predisposition towards thrombosis increases with the number of risk factors present in the patients.