In dogs anaesthetized with pentobarbital hepatic blood flow measured with electromagnetic flowmeters placed on the hepatic artery and the portal vein was 142 +/- 10.2 ml.min(-1).100 g(-1). The flow estimated with the hydrogen clearance technique was 64 +/- 4.4 per cent, with the Xe133 wash-out technique 78 +/- 7.4 per cent and by the uptake of colloidal radiogold 96.5 +/- 5.0 per cent of the direct measurement. In the flow range between 50 and 344 ml.min-1. 100 g-1 the respective correlation coefficient between HBF measured with the hydrogen clearance technique and with the flowmeter was 0.733, between Xe133-HBF and flowmeter HBF 0.785 and between Au198-colloid HBF and the directly measured HBF was 0.815.