Marine-derived fungi have proven to be rich sources of structurally novel and biologically active secondary metabolites, which are emerging as a significant resource for new chemicals in drug discovery.[1] During a search for natural products that exhibit pharmacologically interesting activities,[2] we screened extracts derived from marine organisms for cytotoxic activity. Herein we report the isolation, structure elucidation with the absolute stereochemistry, and biological activities of four new doubly prenylated indole alkaloids, the notoamides A–D (1–4). These alkaloids were obtained from a culture of marine-derived fungus, Aspergillus sp., which was isolated from the common mussel, Mytilus edulis. Biogenetically, the notoamides are assumed to be related to each other, and Williams and co-workers report their successful biomimetic syntheses of notoamides C (3) and D (4) in a following Communication.[3]