Background: Lower extremity venous thrombosis (LEVT) is the most frequent form of vascular involvement in Behcet's disease. Up to 17% of the mortality in Behcet's disease is reported to be associated with venous involvement such as pulmonary embolism or Budd–Chiari syndrome (BCS). Early recognition and appropriate management of vascular involvement in BD is essential to reduce associated morbidity and mortality. Homocysteine (hcy) may play a role in BD patient with venous affection. Objectives: To find out the role of homocysteine and venous Doppler ultrasonography in detection of venous insufficiency (VI) in BD patients. Subjects and Methods: A case control study, 50 patients with Behcet's diseaseand 50 age and sex matched healthy controls were included. Serum homocysteine (by ng/l) was determined by ELISA. Also measurement of VI by venous Doppler ultrasonography in lower limbs of Behcet's patients and controls. Results: In this study there was statistically significant difference between serum homocysteine level among BD patients and controls (p < 0.05). There was a significant difference between serum homocystiene levels in BD patients with venous versus non venous affections, p<0.05. There was a significal positive correlation between serum hcy levels and VI grades by Doppler US. Conclusions: Behcet's disease patients with hyperhomocysteinaemia and VI diagnosed by Power Doppler US should be considered as a strong indicator of pathological venous involvement.