Fungal infections may account for 5-50% of serious infections in intravenous drug users, and for 5-50 per 100,000 hospital admissions. The fungi most commonly encountered are Candida and Aspergillus spp. Candidosis may be disseminated, with lesions in superficial structures, the eye and the skeletal system, or limited to the eye, the heart (as endocarditis) or the central nervous system. Aspergillosis usually presents as endophthalmitis or as central nervous system infection. Mucormycosis is also met with occasionally, and various fungi may cause endophthalmitis or endocarditis. Antifungal therapy for intravenous drug use-related infections is no different from that for similar mycoses in other patients, but the management of intravenous drug users requires considerable clinical skill.