Reproductive failure (recurrent foetal loss, unexplained infertility and IVF implantation failure) may be, in a number of cases, explained by thrombophilia, either acquired or inherited. Several genes contribute to thrombophilia, some with major effect (Factor V, Factor II), and some with minor effect (MTHFR, PAI-1, ATIII, etc.). The aim of this study was to estimate frequency of thrombophilia-associated genotypes (FII20210G>A, FV1691G>A, MTHFR677C>T and PAI-1 -675 4G/5G) in a group of 1631 Serbian women experiencing reproductive failure, and compare it with a healthy, female control group. Our results showed marginally significant (p=0.050) differences in allele frequencies between patients and controls for the FV1691 mutations. For the FII20210G>A, although the statistical significance was not achieved (p=0.076), we found higher frequency of variant allele in patients compared to controls (1.87% vs. 0.38%, respectively) which may point to a possible role of this polymorphism in thrombotic events. For the MTHFR677C>T and PAI-1 -675 4G/5G, we found no difference in distributions of genotype or allele frequencies between these two groups (p>0.05). For three subjects with very rare genotypes (two patients homozygous for FV1691G>A and one patient homozygous for FII20210G>A) we performed additional biochemical analyses for haemostasis, as well as genotyping of two polymorphisms (MTHFR1298A>C and ATIII786G>A).