In Vietnam, the range and relative contribution of organisms causing CAP remain unclear, largely because diagnostic tools are limited and clinical research uncommon. An improved understanding of the risk factors, etiology and clinical outcomes of CAP in Vietnam would contribute to improved approaches to patient diagnosis and clinical management. This will be achieved by following the clinical and laboratory progress and treatment outcomes of in-patients diagnosed with CAP from admission to discharge. Comparative analyses will be between subgroups including survivor and non-survivor, severe CAP and non-severe CAP, known etiology and unknown etiology, SIRS, sepsis, severe sepsis and shock septic.