We investigated the in vitro activity of caspofungin compared to amphotericin B, fluconazole, and itraconazole against clinical strains of Candida spp. (n =239). Antifungal susceptibility tests were done in accordance with NCCLS M27-A2 microdilution method and the results were read after 24 and 48 h. In general, 24 h MIC readings were similar to those at 48 h for most isolates and all antifungal agents. Caspofungin was active against all species tested. Caspofungin MICs of Candida parapsilosis were slightly higher than those for other Candida spp. Caspofungin MIC (microg/ml) ranges at 24 h for C. albicans, C. glabrata, C tropicalis, C. parapsilosis, C kefyr, C krusei, C. lusitaniae, C. norvegensis, C. guilliermondii and C. lipolytica were 0.06-2, 0.125-2, 0.125-2, 1-4, 0.125-2, 1-2, 0.5-2, 0.5-1, 0.5-2 and 1-2, respectively. Eagle (paradoxical) effect was observed in 31 and 8% of the isolates at highest concentrations of caspofungin and itraconazole, respectively. The activity of caspofungin against fluconazole- and/or itraconazole-resistant isolates was similar to that detected for the susceptible ones. We conclude that caspofungin appears as a promising antifungal agent with enhanced activity against Candida, including the azole-resistant strains.