We investigated factor VIII (FVIII) gene mutations in 20 thrombosis patients with high level of FVIII and 20 control healthy participants. Blood samples were used for the determination of FVIII levels using static timing analyze (STA) kits. Informed consent forms were collected from all participants. Factor VIII level was 237 +/- 46 IU/dL in patients group; however, it was 122 +/- 38 IU/dL in healthy control participants. Isolated genomic DNAs were screened using 37 pairs of primers covering promoter region and 26 exons of FVIII gene. Single-strand conformation analysis (SSCA) technique was performed for polymorphism/mutation analyses. We observed polymorph patterns in exon 6, exon 13, exon 14F, exon 19, and exon 25 regions. However, we found no evidence of an association between observed single nucleotide polymorphisms and high thrombosis levels. In conclusion, observed exons polymorphisms do not seem to be associated with a venous thromboembolism.