Pneumonia is defined as inflammation and consolidation of lung tissue due to infectious microorganisms. Community acquired pneumonia is a syndrome in which acute infection of the lungs develops in persons who have not been hospitalized recently and have had little contact to the health care system. It is a common condition and its attack rates are highest in elderly persons. Community acquired pneumonia can vary from a mild outpatient illness to a more severe disease, requiring admission to a hospital or even an intensive care unit and it remains an important cause of morbidity and mortality. Streptococcus pneumoniae is the most common pathogen and Respiratory Syncitial virus is the most common important viral pathogen in children. Therapeutic strategies are usually empiric, based upon demographic and epidemiologic factors. In this manuscript, epidemiology, etiology, risk factors, diagnosis and treatment of community acquired pneumoniae are summarised