Purpose. To describe a Doppler waveform index representing the hepatic vein flow velocity pattern and to examine its relationship to the degree of hepatic fibrosis. Methods. Doppler waveforms were obtained in 66 patients scheduled for percutaneous liver needle biopsy and categorized as normal (with a retrograde flow phase) or abnormal (without retrograde flow). Waveforms were also characterized using a hepatic vein waveform index (HVWI): (maximum - minimum velocity)/(maximum velocity). Biopsy specimens were graded for fibrosis. Results. There was a highly significant decrease in HVWI with increasing fibrosis score in the biopsy (p < 0.001, Jonckheere trend test). The biopsy showed cirrhosis in 14 of 29 patients (48%) with absent retrograde flow and 5 of 37 patients (14%) with a normal flow pattern. Using HVWI as the criterion, cirrhosis was present in 13 of 21 (62%) patients with HVWI < 0.75, in 6 of 31 (19%) patients with 0.75 < HVWI < 1.50, and in none of 14 (0%) patients with HVWI > 1.50. Conclusions. HVWI is inversely correlated to the degree of liver fibrosis and may be more efficient than the presence or absence of retrograde flow in diagnosing and grading hepatic fibrosis.