<p>A severe complication of the treatment of pediatric cancers is the development of an invasive fungal infection (IFI). The data to support antifungal prophylaxis in pediatric oncology patients derive primarily from adult patients, and thus the optimal agent to utilize is not clear. Fluconazole has been a standard option, but agents with antimold activity are now available, each with limitations. Pediatric dosing for voriconazole and posaconazole is uncertain and multiple drug interactions exist. The echinocandins are well-tolerated, but only available in intravenous form. Ultimately, studies demonstrating biologic risk factors for the development of IFI may lead to personalized prophylactic strategies.</p>