Innate immunity is first line of defense that we born with, which recognize pathogen or damage associated molecular patterns via germ-line encoded pattern recognition receptors such as TLRs and its rapid pleiotropic response. The recognition of such molecular patterns initiates the synthesis of cytokines and chemokines, and the phagocytosis of invading pathogens by phagocytic cells; both of them are vital features for initiating a protective inflammatory response. Furthermore chemoattractant of monocytes and neutrophils from the blood circulation and activation of macrophages and bridging innate to adaptive immunity are consequent phases in the host defense against invading pathogens. While innate immune cells are the first line of defense they play a critical role in the activation and development of adaptive immune responses. Activation of antigen-presenting cells as dendritic cells is an essential step for initiation of adaptive immunity. Furthermore innate immunity contributes in the elimination of pathogens that have been targeted by adaptive immunity. All these complex orchestrated mechanism were discussed in this book and you will see how our body control infections