Three new malyngamides, U (1), V (2), and W (3), all possessing an uncommon oxygenation pattern, have been isolated from the marine cyanobacterium Lyngbya majuscula collected in Papua New Guinea. The planar structures of these compounds were deduced from NMR data. Aspects of their relative stereochemistry were investigated using selective (1)H decoupling, 1D and 2D NOESY, and E-COSY experiments in three different NMR solvents.