Community-acquired pneumonia is one of the most common infections seen in emergency department patients. There is a wide spectrum of disease severity and viral pathogens are common. After a careful history and physical examination, chest radiographs may be the only diagnostic test required. The first step in management is risk stratification, using a validated clinical decision rule and serum lactate, followed by early antibiotics and fluid resuscitation when indicated. Antibiotics should be selected with attention to risk factors for multidrug-resistant respiratory pathogens. Broad use of pneumococcal vaccine in adults and children can prevent severe community-acquired pneumonia.