LY121019 is a new semisynthetic lipopeptide antifungal agent with potent in vitro fungicidal activity against multiple clinical strains of Candida albicans and Candida tropicalis but is 10-100 fold less active against Torulopsis glabrata and Candida parapsilosis. Its in vitro activity against Candida albicans and Candida tropicalis is comparable to that of amphotericin B. The in vitro fungicidal activity of this new agent supports further investigations into its use in treatment of Candida infections.