A metalloanthocyanin, cyanosalvianin, was found in blue petals of Salvia uliginosa. Cyanosalvianin consisted of 3-O-(6-O-p-coumaroylglucopyranosyl)-5-O-(4-O-acetyl-6-O-malonylglucopyranosyl) delphinidin, 7,4'-di-O-glucopyranosylapigenin and magnesium ion. We reproduced the same blue color as the petals by mixing the three components together. An ESI-MS measurement gave a molecular weight of 9014 indicating the composition of cyanosalvianin to be six molecules of the anthocyanin component, six molecules of the flavone component and two magnesium ions. The special arrangement of the organic components in cyanosalvianin was analyzed by CD and 2D-NMR spectroscopy. It was clarified that cyanosalvianin has a similar structure to that of commelinin, a metalloanthocyanin isolated from blue dayflower, Commelina communis.