Two new cyclic hexadepsipeptides, exumolides A (1) and B (2) were produced by a marine fungus, identified as a Scytalidium sp., collected in the Bahamas. Two dimensional NMR methods, coupled with tandem mass spectrometry (MS-MS), were used to establish the structures of the new compounds. The exumolides exhibit antimicroalgal activity against the unicellular chlorophyte Dunaliella sp. at 20 lag ml "l in liquid media cell growth assays.