The community-acquired pneumonia is a common and serious illness. Pneumonia is said to be community acquired if it is contracted outside of hospital environment or if it is diagnosed within the first 48 hours of hospitalisation. The pathogen remains unknown after investigations in around 50%. The patient should initially be treated empirically, based on the likely pathogens according to the patient's risk-factors, underlying diseases, severity of pneumonia and place of therapy. If recent guidelines are compared (American Thoracic Society, British Thoracic Society and the Infectious Disease Advisory Board) there are differences concerning epidemiology, patients classification and the empiric antibiotic treatment. The appearance of resistances and the recent availability of new antibiotics account partially for these differences. In order to avoid further resistances but still achieving an efficient treatment, coherent antibiotic schemes considering local microbiological epidemiology and patients classifications must be applied as proposed by different guidelines.