Aurantosides D−F (4−6), new polyene tetramic acids comprising an N-trisaccharide unit, have beenisolated from the marine sponge Siliquariaspongiajaponica. Their structures were determined by spectraland chemical methods. A reinvestigation of NMR data of the previously isolated aurantosides A and Bled to revision of the geometry of the terminal double bond. Aurantosides exhibit potent antifungal activityagainst Aspergillus fumigatus and Candida albicans.