The portal blood velocity and flow were measured by means of pulsed echo-Doppler in 60 normal subjects of 4 different age groups (less than or equal to 40, 41-55, 56-70, greater than or equal to 71 years). All subjects had normal routine liver function tests and no history of liver disease. Portal blood velocity decreased from 15.7 +/- 3.2 cm/s in younger subjects to 12.4 +/- 1.7 in subjects over 71 years (ANOVA: p = 0.005). Similarly portal blood flow decreased (p = 0.025). Both portal blood velocity and flow were inversely correlated with age (r = -0.583 and -0.505, respectively). No changes in portal vein diameter were observed. The age-related decline in portal flow may account for the decrease in hepatic blood flow previously documented in the elderly.