Fungal infections in the immunocompromised cancer patient may threaten survival and represent a major therapeutic challenge. Granulocytopenia, especially, increases the risk of infection with the two most common fungal species, Candida and Aspergillus. In cancer patients, mucocutaneous disruptions due to administration of chemotherapeutic agents and use of IV lines, Hickman catheters, and nasogastric tubes provide portals of entry for Candida species. Although cryptococcosis, histoplasmosis, and coccidioidomycosis have gained recent attention because of their increasing prevalence in patients with AIDS, these infections are also seen in cancer patients, especially those receiving corticosteroids. In cancer patients, candidiasis can range from asymptomatic oral thrush to life-threatening candidemia. Although amphotericin B remains a mainstay of treatment, therapeutic and preventive approaches with newer agents such as flucytosine and fluconazole may improve prognosis.