The aim of present study was to investigate the prevalence of factor V Leiden (FVL) c.1691G>A, prothrombin g.20210G>A and methylenetetrahydrofolate reductase (MTHFR) c.677C>T in deep vein thrombosis (DVT) patients and their possible association with DVT in western Iran. Eighty DVT patients with the mean age of 42.07 +/- 13.0 years including 44 women and 36 men and 100 sex-matched healthy individuals with the mean age of 37.63 +/- 13.3 years from Kermanshah Province of Iran with ethnic background of Kurd were studied for FVL c.1691G>A, prothrombin g.20210G>A and MTHFR c.677C>T by PCR-restriction fragment length polymorphism (RFLP) method using MnlI, HindIII and HinfI restriction enzymes, respectively. Prevalence of FVL was 11.4% in patients and 2% in control group. A significant association was found between FVL mutation and DVT with odds ratio (OR) of 6.3 [95% confidence interval (CI) = 1.32-30.05; P = 0.012]. The prevalence of prothrombin g.20210G>A variant in patients (3.8%) was nonsignificantly higher than control individuals (1.0%; OR 3.8; 95% CI = 0.39-37.81; P = 0.32). The prevalence of MTHFR c.677C>T in patients was 38.7% that was not statistically different from control group (44% P = 0.12). Venous thrombosis in legs was the most frequent clinical manifestation (n = 75), corresponding to 93.8% of the thromboembolism, followed by pulmonary thromboembolism (6.2%). We have, for the first time, determined the prevalence of inherited thrombophilia in a homogenous ethnic group of DVT patients and shown that FVL may be a risk factor for DVT in western Iran.