After a surgical intervention patient can face pulmonary complication that was formerly recognised as postoperative pneumonia. This term described the clinical picture which was diagnosed after abdominal or thoracic operations, after polytraumatic lesions, especially with elderly patients that were for a longer time confined to bed rest. The clinical symptoms incl. the X ray picture were consistent with those of pneumonia - such pneumonias are nowadays classified as nosocomial infections. These complications sometimes ended fatally. The post-mortem examination revealed either pneumonia or often pulmonary thromboembolism (PTE). Occasionally it happened that PTE was incorrectly clinically diagnosed as pneumonia and the patient was treated with antibiotics instead of with heparin. The present paper brings discussion on the differential diagnosis between postoperative nosocomial pneumonia and PTE. Clinical casuistic is also added.

        Key words: nosocomial pneumonia, postoperative pneumonia, inhalation pneumonia, pneumonia in surgery, pulmonary thromboembolism, thrombophilia.