Abstract Glycolipids with blood group A activity were purified from hog stomach mucosa powder. The active lipids were isolated by chloroform-methanol extraction, partition with aqueous KCl followed by precipitation of the polar lipids with acetone. Then the A active glycolipids were purified by DEAE-cellulose and Florisil column chromatography. Final purification of the A active compounds was achieved by sequential preparative thin layer chromatography in two solvent systems. The homogeneity of the purified fractions was confirmed by thin layer chromatography in neutral, acidic, and basic solvent systems, thin layer chromatography of the acetylated derivatives of the purified fractions and by osmium-catalyzed periodate oxidation followed by paper chromatography of the released oligosaccharide chains. Two similar but distinct A active glycolipid fractions (L and U) were isolated. Fraction U contained high amounts of long chain hydroxy fatty acids, while Fraction L was rich in C16-C18 fatty acids. Sphingenine and heptadecasphinganine were the major long chain bases found in both fractions. The carbohydrate composition of Fractions L and U was identical and was found to be (in moles per 1 mole of glucose): galactose, 3.04; fucose, 1.09, N-acetylglucosamine, 0.99, N-acetyl-galactosamine, 0.93. Partial acid hydrolysis, mild acid hydrolysis, enzymatic digestion, and immunological assays established the following carbohydrate sequence for the A active glycosphingolipid isolated from hog stomach mucosa powder: [see PDF for sequence]