The antimicrobial peptide LL-37 belongs to the cathelicidin family and is the unique amphipathic α-helical peptide identified in humans up to date. LL-37 is not only a major protein of blood cells, but is also present in epithelial cells. This peptide has a broad spectrum of antimicrobial activity, which kills bacteria by disrupting membrane according to the “carpet like” mechanism. LL-37 possesses the ability to bind lipopolysaccharide(LPS) and neutralizes its biological activity via its binding activities for LPS and CD14. In addition, LL-37 acts as a chemoattractant to recruit immune cells to site of infection by binding to formyl peptide receptor-like 1 FPRL1. Taken together, LL-37 is a multifunctional modulator of innate immune responses and might have the therapeutic potential for the treatment of bacterial infection and immunocompromise.