Host defense of the lung is characterized by a fine balance between the generation of a vigorous inflammatory response to clear pathogens and maintenance of the integrity of the alveolar gas-exchange surface. The magnitude of the inflammatory response is therefore tightly regulated by pro- and anti-inflammatory cytokine mediators. This article summarizes current information on the roles of specific cytokines in pneumonia, with particular emphasis on ongoing investigations into the role of innate immunity in bacterial and fungal pneumonia.