Pneumonia is one of the most frequent infectious diseases that lead to hospitalization. It is a decisive turning point and frequently leads to death, particularly in old and comorbid people (so-called terminal event). It is classified into community-acquired pneumonia, hospital-acquired pneumonia and pneumonia due to severe immunosuppression. The three entities differ especially in the spectrum of pathogens to be expected, the site of development and therefore in the calculated anti-infective treatment and initial diagnostics. The continuous re-evaluation of the course and the focal points as well as adaptation of the treatment are essential for the optimal outcome of the patient. Even after surviving an acute disease, in cases of possibly deteriorated functional status there is a need for good aftercare with management of comorbidities, social interventions and when necessary, treatment of persisting organ dysfunction. Prophylaxis by vaccination is essential.