The clinical profile of HIV infection has changed from lethal disease, gradually destroying patient's immunologic system and progressing inevitably to AIDS, into a chronic manageable condition as it is now. The introduction of combined antiretroviral therapy in 1996 dramatically improved prognosis. In developed countries the estimated survival for a young person diagnosed with HIV infection in the late highly active antiretroviral therapy approaches the survival of general population. Despite the benefits of early diagnosis, majority of people living with HIV are unaware of their HIV status. Both poor knowledge of transmission routes and long asymptomatic phase of the infection contribute to delayed diagnosis. When the disease progresses towards symptomatic phase many patients seek help of physicians of varied specialities. The correct diagnosis of HIV infection being the cause of the reported symptoms depends on physicians' knowledge of HIV clinical features. In the age of combined antiretroviral therapy the diagnosis of HIV infection saves patient's life, and in case of pregnant women it additionally decreases significantly the risk of vertical transmission.