In geriatric practice, data regarding infections including the epidemiology, morbidity, and mortality are lacking. Our aim was to evaluate the frequency, location, microbiological and laboratory characteristics of infectious diseases in elderly population admitted to a training hospital. The patients were included total of 330 patients, aged over 65 with infection, seen between January 1, 2005 and January 1, 2006. In the result, of patients 136 (41%) had respiratory system infection, 90 (27%) urinary system infection, 39 (12%) gastrointestinal system infection, 34 (10%) bloodstream infections, 17 (5%) soft tissue infection, 8 (2%) central nervous system infections, and 6 (2%) others. Average length of hospitalization was 8.6±7.7 days. Mortality rate from all causes was 57 (17%). The most common infections in elderly patients were respiratory tract and urinary system infections, and there were no fever, leukocytes and high CRP levels in approximately 1/3 of cases. Infectious diseases may occur even in the absence of such infection indicators as fever, raised WBC count and high CRP level in the elderly population.