Two glycosphingolipids with human blood group A and H antigenicity were isolated from porcine erythrocyte membranes which were obtained from the pooled blood. The yield of the A- and H-antigenic glycolipids was approximately 0.2 and 0.1% of total neutral glycolipids, respectively. No B antigen was detected. Through several methods the porcine erythrocyte antigens were all found to belong to lactoseries (type 1 chain), IV2Fuc alpha, IV3GalNAc alpha Lc4Cer for type A and IV2-Fuc alpha Lc4Cer for type H, in contrast to the antigenic glycolipids in human erythrocytes, which mostly belong to neolactoseries (type 2 chain). The constituent fatty acids of the A antigen were 75% normal acids and 25% 2-hydroxy acids, and the long chain base was 95% sphingenine. This is the first demonstration of the A- and H-antigenic glycolipids on erythrocytes of pig in whose gastric mucin the human blood group A and H substances have been demonstrated.