The increased risk for thrombosis is known as hypercoagulability or thrombophilia. Here, we investigated risk factors for thrombophilia which were screened in young adult patients presenting with thrombotic events or with recurrent abortions with unknown etiology. A total of 115 patients aged between 16 and 50 years who were found to harbor thrombophilia were retrospectively evaluated. The laboratory investigations performed for the assessment of thrombophilia included protein C, protein S, antithrombin III deficiencies, activated protein C resistance, factor V Leiden (FVL), prothrombin 20210A (PT 20210) and methylenetetrahydrofolate reductase (MTHFR) gene mutations, factor VIII elevation, lupus anticoagulant and antiphospholipid antibodies (APA). In 66% of the cases a single thrombophilic defect was identified while some of the patients had combined thrombophilic defects. The most common thrombophilic defect was mutation in the MTHFR gene, and was followed by FVL mutation, the presence of APA and PT 20210 gene mutation, respectively. The patients were divided into two different age groups, 16-35 and 36-50 years, and arterial thrombosis was more common in the older age group. Our results indicated that some important thrombophilic defects such as gene mutations may appear in young adult patients presenting with thrombotic events.