Community-Acquired pneumonia (CAP) remains a major health problem worldwide. The incidence of pneumonia increases with both age and the presence of specific risk factors, which lead to increased health care costs. However, although there is some controversy over the observed trend in CAP mortality over recent decades, it is clear that mortality in CAP patients who require intensive care unit care remains high. The increase in antibiotic resistance is an important global health problem that needs to be addressed, especially for pneumococcus the most frequent pathogen of CAP. The prudent use of current antibiotics will help to limit the spread of antibiotic resistant clones of pneumococcus. Pneumococcal and influenza vaccinations remain the primary strategy for the prevention of CAP, especially in an at-risk population. This article reviews CAP, with a focus on epidemiology, diagnosis, prognostic factors, microbial etiology, therapy, complications, and prevention.