Lactoferrin (Lf) is an iron-binding glycoprotein of the transferrin family that is expressed and secreted by glandular cells and found in the secondary granules of neutrophils from which it is released in infected tissues and blood during the inflammatory process. Initially described as an iron-binding molecule with bacteriostatic properties, Lf is now known to be a multifunctional or multi-tasking protein. It is a major component of the innate immune system of mammals. Its protective effects range from direct anti-microbial activities against a large panel of microorganisms including bacteria, viruses, fungi, and parasites, to anti-inflammatory and anti-cancer activities. While iron chelation is central to some of the biological functions of Lf, other activities involve interactions of Lf with molecular and cellular components of both hosts and pathogens. Its powerful antimicrobial activities, immunomodulatory properties and prevention of septic shock, anti-carcinogenic functions and its growing importance in iron delivery and bone growth, combined with the data obtained either by in vivo studies or clinical trials, make this molecule and its derivatives very promising tools for health or nutritional applications.