Abstract.Bile salt sulphates were determined in serum and urine of 40 patients with severe cholestasis due to extrahepatic obstruction, hepatitis, cirrhosis and metastases of the fiver. Mono‐, di‐ and tri‐sulphates of bile salts were identified by column chromatography following intravenous administration of14C‐cholate. Quantitative analysis was done by gas‐liquid chromatography following solvolysis. In our patients more than 50% of the bile salts excreted by the urine were sulphated (76.9% mono‐sulphates, 21.3% di‐sulphates, 1.8% tri‐sulphates). In contrast less than 10% of serum bile salts were sulphated. Therefore the renal clearance of bile salt sulphates was more than 15 times greater than the clearance of non‐sulphated bile salts. There were no significant differences in patients with extrahepatic obstruction, hepatitis, cirrhosis and metastases of the liver. – It is concluded that urinary excretion of mono‐ and di‐sulphates of bile salts represents an important excretory mechanism in patients with cholestatic liver disease. In most patients only trace amounts of tri‐sulphated bile salts w