Average life expectancy in developed countries has rapidly increased in the middle of the 20th century and the geriatric problems have become an increasingly important issue. Many diseases in the elderly are more frequent and more severe in comparison to the younger population. This is certainly true for the infectious diseases which are in the elderly associated with poor outcome, moreover they have often the distinct features with respect to clinical presentation, laboratory and imaging test results, microbial epidemiology, and methods of treatment. The most important reasons why the diseases in the elderly are more frequent and more severe these are: typical for advanced age immunosenescence, malnutrition, large number of age-associated social, psychological, economical, moreover physiological and anatomical alterations. The older HIV positive adults, have lower CD4 counts at moment of diagnosis, faster progression to AIDS, more opportunistic infections, shorter survival rate than younger adults--regardless of when they were first diagnosed with HIV.