Introduction: Acute venous or arterial thrombosis in young women represents a rare event, which can have high mortality. In the absence of classic risk factors, prothrombotic gene variants could play a role in thrombosis at young age. The present study aimed to evaluate the contribution of thrombophilic mutations to acute thrombotic events in this population. Methods: We studied Factor V Leiden, Factor II G20210A mutation, MTHFR C677T and A1298C variants by real-time PCR in 68 young women with acute thrombotic events (23 patients with acute myocardial infarction, AMI, and 45 patients with venous thromboembolism, VTE) with no known conventional risk factors. The data were compared to those obtained from 131 unrelated female subjects from the general population of the same geographical area. Results: Mean age in the study group was 29.8 ± 8.3 years in the VTE group and 39.2 ± 8.2 years in the AMI group. In young VTE females, the allelic frequency of FV Leiden was significantly higher versus the general population. We found a very high frequency of both MTHFR mutations in the general population (45% for heterozygote status and 5 – 10% homozygote status), comparable to that demonstrated in the acute thrombosis groups. Mean levels of blood homocystein were similar among the 2 groups (12.0 ± 3.9 vs 10.6 ± 3.1 mcg/dl, p = 0.38), mostly in the normal range. Conclusions: Our data confirm that young VTE, but not AMI female patients can associate genetic mutations with an increased plasma procoagulant activity of FV Leiden. On the contrary, MTHFR mutations are not related to increased levels of homocysteine in this population, having a similarly high prevalence as in the general population. Understanding the distribution of such risk factors may help improve the management strategies for acute thrombotic events in young women.