Invasive fungal infections have become an increasing problem in older adults. Infections with opportunistic fungi have increased because older patients are more likely to be considered for transplantation, receive aggressive regimens of chemotherapy for cancer, and take immunosuppressive drugs for nonmalignant diseases. In addition, healthy older adults are now more likely to travel extensively and to indulge in outdoor activities, which put them at risk for exposure to endemic mycoses. Although many of the clinical manifestations of fungal infections in older and younger adults are similar, there are aspects of histoplasmosis, aspergillosis, and cryptococcosis that are unique to older patients. Treatment of older adults with amphotericin B is difficult because of the intrinsic nephrotoxicity of the drug. Although they are less toxic, azoles must be used carefully for treatment of older adults, who are more likely to experience serious drug-drug interactions than are younger persons.