Normal values and upper limits (95th percentile) of liver, spleen, pancreas, and portal vein size were determined prospectively with ultrasound in 915 healthy subjects. Sex, age, weight, height, and body surface area were determined in each case. Since correlation of longitudinal and transverse organ diameters with physical data was poor (r less than or equal to 0.3), the authors do not consider it necessary to correct the measurements accordingly. However, the liver is oriented longitudinally in slender subjects and transversely in heavy subjects; thus both longitudinal and anteroposterior diameters need to be measured, since the longitudinal diameter alone will give too high or too low a value, respectively.