PVT is often multi factorial disease. This study was undertaken to determine the prevalence of FII 20210 G - A mutation as a risk factor for idiopathic portal vein thrombosis in the pediatric age group.40 children with idiopathic portal vein thrombosis and 20 healthy age matched controls were included in this study. They were subjected to :•Routine lab investigation : CBC, PT, PTT, and liver function tests. •Special lab investigation : Protein C assay, Protein S assay, antithrombin III assay, APC-resitance assay, and DNA analysis to detect factor II mutation and factor V mutation.Prevalence of factor II 20210 GA (15%) and the control (0%), factor V mutation was found in 12 cases (30%) and one of the control group (5%), 11 cases (27.5%) had protein C deficiency, one case (2.5%) had antithrombin III deficiency, and protein S deficiency was not found in any case.