The primary aim was to determine frequencies of mutations related to risk of venous thrombosis in healthy Caucasians in Central Bohemia. In a cohort of 1527 healthy individuals the frequency of risk alleles for the mutations FV Leiden and FII 20210G>A was 4.5 % and 1.3 %, respectively. Frequency of 4G PAI-1 allele was 55.5 %. Genotype frequencies were: GG 91.03 %, GA 8.91 %, an d AA 0.07 % for FV Leiden; GG 97.45 %, GA 2.49 %, and AA 0.07 % for FII 20210G>A; 4G/4G 30.26 %, 4G/5G 50.56 %, and 5G/5G 19.19 % for PAI-1. Frequency of the risk allele A in polymorphism SERPINC1 (IVS +141G >A) was 11.3 %, and frequencies of genotypes were as follows: GG 78.36 %, GA 20.66 %, and AA 0.98 %. Frequency of the risk allele T for polymorphism GP6 13254T>C was 87.7 %, and frequencies of genotypes were as follows: TT 77.14 %, TC 21.15 %, and CC 1.70 %. Frequency of the risk allele A in polymorphism CYP4V2 (Lys259Gln ) was 65.2 %, and frequencies of genotypes were: CC 12.25 %, CA 45.12 %, and AA 42.63 %. All observed genotypes and alleles frequencies were without gender differences. Their occurrences confirm a relatively high prevalence of hereditary thrombophilia predisposition in the Czech Republic., T. Kvasnička ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy