Nosocomial pneumonia (hospital-acquired pneumonia - HAP) is the form of pneumonia the symptoms of which present after more than 2 days (> 48 hours) of admission to hospital or as late as 14 days of discharge from hospital. The HAP pneumonias represent 13-18 % of all nosocomial infections. Incidence of HAP is the most frequent in mechanically ventilated patients. The type and representation of HAP agents primarily depends on the length of a patients stay in hospital and on their condition and character of treatment. Diagnosing of pneumonia is based on anamnesis, physical and X-ray findings, results of examination of microbiological samples from the respiratory tract, hemoculture, the pleural effusion test, serological, hematological and biochemical tests. Antibiotic treatment is key to the comprehensive treatment of HAP. The HAP treatment always requires the dosing of antibiotics near the upper limit of the possible range. A precondition for successful avoidance of HAP pneumonias is the creation of a preventive programme with active engagement of medical staff.Key words: diagnostics - HAP pneumonia - treatment - ventilator-associated pneumonia.