Antimicrobial (host defense) peptides have been implicated to play an important role in many different biological settings, including infection, inflammation, cancer and autoimmunity. These short peptides can exert a multitude of functions and simple biochemical modifications can be used to steer their functionality to either improve or dampen desired or unwanted effects. This multifunctionality and biochemical flexibility has opened up a wide field of potential applications for synthetic antimicrobial peptides, which are being developed at a rapid pace. Therefore, the 2019 Gordon Research Seminar on Antimicrobial Peptides will focus on topics ranging from the discovery of novel functions and mechanisms of action of natural antimicrobial peptides in health and disease to their innovative research on therapeutic applications.