Invasive fungal infections occur in 5% to 45% of solid organ transplant recipients, and are a major cause of morbidity and mortality in the immunocompromised population. The net depression of host defenses and environmental factors, such as preoperative exposures to endemic mycoses or nosocomial and specific surgery-associated exposures, affect the development of invasive infection. Most fungal infections in solid organ transplant recipients occur within the first 2 months after transplantation. The most common pathogens in the majority of solid organ transplant recipients are Candida spp, followed by Aspergillus sp. Diagnosis is best made by a high index of suspicion and aggressive acquisition of specimens for culture; serologic tests are useful for infections due to Cryptococcus neoformans and Histoplasma capsulatum. Amphotericin B is the drug of choice for life-threatening infections. The triazoles, fluconazole and itraconazole, may be effective alternatives for less serious infections due to susceptible organisms. Prophylactic and preemptive treatment strategies require further study.