Fungal infections have assumed an increasingly important role as use of broad-spectrum antimicrobial agents has increased and the number of immunodeficient patients has grown. Some pathogens (eg, Cryptococcus, Pneumocystis, Fusarium) rarely cause serious disease in immunocompetent hosts. Other endemic fungi (eg, Histoplasma, Coccidioides, Paracoccidioides) commonly cause disease in immunocompetent persons but tend to be more aggressive in immunocompromised ones. Superficial mycoses are discussed in Chapter 6. Successful management of most systemic fungal infections requires knowledge of the natural history of these diseases and the specific tests needed to make a diagnosis as well as familiarity with the unique pharmacokinetics, adverse effects, and drug interactions of the various therapeutic agents. Consequently, clinicians with extensive experience in the management of fungal infections should be routinely consulted.