Caspofungin is the first echinocandin to be approved for the treatment of fungal infections in pediatric patients. The antifungal properties of caspofungin result from interference with fungal cell-wall integrity. In vitro, caspofungin is fungicidal against Candida spp. and fungistatic against Aspergillus spp., but has little or no fungicidal or fungistatic activity against Cryptococcus neoformans, the Zygomycetes, Fusarium spp., or Trichosporon beigelii. Caspofungin was effective as empirical antifungal therapy in pediatric patients with persistent fever and neutropenia. Almost half (46%) of caspofungin recipients and one-third (32%) of liposomal amphotericin B recipients achieved an overall favorable response in a randomized, double-blind trial. Caspofungin was also effective in pediatric patients with fungal infections (invasive candidiasis, invasive aspergillosis refractory to or intolerant of standard antifungal agents, or esophageal candidiasis). Positive responses to treatment were seen in 30 of 37 patients with invasive candidiasis, 5 of 10 patients with invasive aspergillosis, and in the one patient with esophageal candidiasis, in a noncomparative, open-label trial. Caspofungin was generally well tolerated in the clinical trials in pediatric patients with febrile neutropenia requiring empirical antifungal treatment, or with fungal infections. Few caspofungin recipients reported serious drug-related adverse events or discontinued treatment as a result of drug-related adverse events.