A series of 29 artemisinin derivatives (2-30), including four new compounds (16-18, 20), together with artemisinin (1), artemisinic acid (31), and arteannuin B (32), were tested for antifungal activity against two opportunistic pathogens, Candida albicans and Cryptoccocus neoformans. Of all the compounds tested, anhydrodihydro-artemisinin (3) demonstrated more potent antifungal activity against C. neoformans than amphotericin B. Also, beta-arteether (7) and alpha-arteether (8) showed marked activity against C. neoformans. Against C. albicans, the overall antifungal effect of these compounds was weak or negligible. Derivatives 2-30 were prepared according to literature procedures.