Two cytotoxic alkaloids, discorhabdins L (1) and I (2), were isolated from Latrunculia brevis and their structures assigned on the basis of detailed spectroscopic analysis and comparison with the known metabolites discorhabdins R (5), D (6), and B (4). Compounds 1 and 2 showed strong in vitro cytotoxicity against a panel of 14 tumor cell lines.