The structures of sporaricins A and B have been determined to be 2-amino-l-O-(2,6-diamino-2,3,4,6,7-pentadeoxy-β-L-lyxo-heptopyranosyl) -2,3,5- trideoxy-5- (N-glycyl -N- methyl-amino) -4-O-methyl-D-chiro-inositol and 2-amino-l-O-(2,6-diamino-2,3,4,6,7-pentadeoxy-β-L-lyxo-heptopyranosyl) -2,3,5-trideoxy-4-O-methyl-5-methylamino-D-chiro-inositol, respectively. © 1979, JAPAN ANTIBIOTICS RESEARCH ASSOCIATION. All rights reserved.