Marine microorganisms such as bacteria and fungi inhabit virtually any environment in the sea, and they are rich sources of chemically and biologically diverse compounds. In our search for bioactive compounds in marine microorganisms, two new halogenated alkenoates, methyl 2,4dibromo-5-oxo-2-decenoate (1) and methyl 2,4-dibromo-5oxo-3-decenoate (2), and the known sesquiterpenediol, cycloneroidol (3), were isolated from the broth of an unidentified fungus, which was separated from the surface of the marine red alga Gracillaria verrucosa collected at Jinha, Ulsan in 2002.