Community-acquired pneumonia are potentially life threatening infections for which accurate diagnosis and adequate antibiotic treatment are mandatory. S. pneumoniae remains the first bacterial agent and, is responsible, with L. pneumophila of most of fatal issues. Analysis of risk factors and severity signs by practitionners is required to properly manage such infections, Microbiological documentation is scarce in ambulatory medecine and account for less than 50% of hospitalised patients; thus, antibiotic treatment is empirical in most of cases. Amoxicillin remains drug of choice for ambulatory or hospitalized patients without risk factors or severity signs in medical wards, pristinamycin is recommended when an atypical agent cannot be rule out. Respiratory quinolone, mainly levofloxacin, can be prescribed in high risk patients, or in case of a failure of a first line of treatment.