The study of the carbohydrate moiety of actinoidins A and B was found with partial acid hydrolysis of the antibiotics and their methyl derivatives, and periodate oxidation. Actinoidins A and B had 3 carbohydrate branches: the residues of monosugars of D-mannopyranose and 2,3,6-tridesoxy-3-amino-4-O-methyl-L-arabinopyranose(L-actinosamine) and the disaccharide of 2-O-(2, 3, 6-tridesoxy-3-amino-L-arabinopyranosyl)-D-glucopyranose.