Hospital acquired pneumonia (HAP) is a common discharge diagnosis in patients admitted both to surgical and medical wards, and it seems to be associated with increased mortality and morbidity. Recent epidemiological data points to an incidence roughly between 0.5 and 2%. Ventilator associated pneumonia accounts for about 1/3 of these episodes. Still, there is scarce information regarding HAP distribution, risk factors, the impact of age, differences between surgical and medical patients, strategies for prevention (outside the intensive care unit), and health costs, especially hospital length of stay and mortality. METHODS: Exploratory analysis of the Portuguese National Health Service (NHS) hospital discharge diagnosis database. All adult inpatients discharged between 2014 and 2017 with a new diagnosis of pneumonia ("not present on admission") were included. Demographic data, type of admission (either medical or surgical), the need for invasive ventilation, hospital length of stay and mortality were collected. This study was approved by the Central Administration of the National Health System.