Fungal infections affect virtually all patients with the Acquired Immunodeficiency Syndrome (AIDS). Superficial infection (seborrheic dermatitis, tinea capitis, tinea corporis and tinea cruris) is more common than in the general population and can be difficult to eradicate. Mucosal disease (oropharyngeal, oesophageal and vaginal candidosis) is very common and often recurs. In advanced AIDS, patients usually fail to respond to topical therapy and often to systemic therapy and isolates of Candida spp. from these patients are frequently resistant in vitro to fluconazole and other azoles. Systemic fungal infection is less common but life threatening. The commonest such infection is Pneumocystis carinii pneumonia (PCP) although prophylaxis is usually successful in preventing either the first episode or recurrent episodes. Histoplasmosis, coccidioidomycosis and Penicillium marneffei infections are common in endemic areas. Cryptococcal meningitis and invasive aspergillosis occur worldwide. The prophylaxis and treatment of all these except PCP are discussed and reviewed.