Patients are asymptomatic during the majority of HIV infection. The virus, however, is actively replicating, producing over 1 billion particles per day during this steady-state of the disease. Management of asymptomatic HIV infection involves initial recognition of infection and counselling to prevent its further spread.When HIV infection has been confirmed, assessment consists of a careful history, physical examination and laboratory studies. The latter include serological tests for past exposure to infectious agents such as syphilis, hepatitis viruses, cytomegalovirus and toxoplasmosis. A purified protein derivative (PPD) skin test should also be performed. The immunological and virological status of the patient is assessed by quantifying CD4+ count and plasma HIV RNA levels. With the aid of these data, a decision can be made on the use of antiretroviral therapy.Didanosine (ddI) is the only currently acceptable monotherapy. Combinations of antiretroviral drugs which have undergone evaluation include zidovudine (AZT) plus didanosine, zidovudine plus zalcitabine (ddC), zidovudine plus lamivudine (3TC), didanosine plus lamivudine, zidovudine plus didanosine plus nevirapine, zidovudine plus saquinavir, zidovudine plus zalcitabine plus saquinavir (D4T), zidovudine plus ritonavir, zidovudine plus lamivudine plus indinavir, and ritonavir plus saquinavir.The optimum combination treatment has not been defined, but many appear promising. In addition, treatment for subclinical infections and prophylaxis should be administered. These include treatment of all PPD-positive patients with isoniazid 300 mg/day orally for 1 year; prophylaxis againstPneumocystis cariniipneumonia for all patients with CD4+ counts <200/mm3with cotrimoxazole (trimethoprim plus sulfamethoxazole) one double-strength tablet daily, dapsone or dapsone plus trimethoprim; prophylaxis against toxoplasmosis in patients with CD4+ counts <100/mm3with cotrimoxazole or with dapsone plus pyrimethamine; prophylaxis against disseminatedMycobacterium aviumcomplex disease in patients with CD4+ counts <75/mm3with azithromycin 1200mg orally once weekly, clarithromycin 500mg orally twice daily, or rifabutin 300 mg/day orally; and prophylaxis againstStreptococcus pneumoniaepneumonia and bacteraemia by administration of the 23-valent pneumococcal vaccine.Although cytomegalovirus disease occurs in most patients with advanced HIV disease (CD4+ <50/mm3), primary prophylaxis is not recommended because of conflicting data concerning the efficacy of oral ganciclovir. Primary prophylaxis against cryptococcosis is not recommended because of the low incidence of this infection.