Aims: Nephrotic syndrome (NS) may occur with acquired hypercoagulability, however, the fact that it is accompanied by an underlying hereditary thrombophilia, especially combined hereditary thrombophilia, would lead to thrombotic events. In this study, we aimed to evaluate the contribution of genetic thrombophilia to development of thrombotic events in adult patients with NS. Material and methods: Factor V Leiden (FVL), prothrombin, and methylenetetrahydrofolate reductase (MTHFR) gene mutation were studied in 51 newly diagnosed idiopathic NS patients and age- and gender-matched 20 healthy control subjects included in the study. Renal vein Doppler ultrasound was conducted in order to investigate the prevalence of subclinical renal vein thrombosis. Results: Of 51 patients, 6 (11.8%) were established to have thromboembolic (TE) complications at the time of diagnosis (4 symptomatic, 2 subclinical), and no recurring thrombotic episode was observed. Genetic mutation was established in all patients that were found to have TB complications. Acquired hypercoagulability factors were similar in patients without and with TE complication. Conclusions: The coexistence of inherited thrombophilia in NS may facilitate thromboembolic complications. If the cause of thrombosis cannot be explained by the usual factors attributed to the occurrence of thrombosis in NS, screening for the other factors, such as FVL, MTHFR, and prothrombin gene mutation, may be beneficial.