Breastfeeding is a recommended practice due to its short and long term benefits for maternal and infant health. It is considered the best and most complete source of nutrients, which contributes to the reduction of maternal and infant morbidity and mortality. One of the components of breast milk is lactoferrin. Its primary function is to collaborate in innate mechanisms of host protection, forming part of the first line of defense of the host that faces direct contact with pathogens that colonize or invade mucosal surfaces. In this text we review the antimicrobial, antiviral and immunological mechanisms by which this glycoprotein contributes to this process.