47-year-old male presented with un-provoked portal and mesenteric vein thrombosis that caused persistent radiating pains of upper abdominal quadrants. The examinations found heterozygous factor II mutation, and family survey for the factor II mutation was recommended. The patient started anticoagulant therapy. In the expert's opinion, the main risk factors for portal vein thrombosis are: Prothrombotic disorder, abdominal inflammation, cirrhosis, cancer, abdominal intervention and abdominal infection.