We have proposed a new technique for sampling hepatic venous blood in conscious dogs. Sub-hepatic vena caval blood flow was temporarily occluded by a previously implanted inflatable snare so that all blood entering the inferior vena cava was hepatic venous effluent. Hepatic venous blood samples were collected from the inferior vena cava 8 seconds after beginning caval occlusion, with the total interval of flow occlusion lasting 12 to 15 seconds. No behavioral or metabolic alterations were observed when or metabolic alterations were observed when hepatic venous effluent was repetitively sampled using the caval occlusion technique. Net splanchnic glucose balance (NSGB) was measured in conscious dogs receiving saline, glucose or glucagon infusions. NSGB measurements made with the caval occlusion technique were in accord with previous results obtained via tracer methodology or arterio-venous difference techniques utilizing hepatic vein catheterization. The caval occlusion technique thus provides a method for collecting hepatic venous blood samples from conscious animals without the difficulties associated with hepatic vein catheterization.