Lunasin, a 43 amino acid polypeptide originally isolated from soybean, is known to produce multiple health benefits, including anti-hypertension, antioxidant activity, cancer prevention or therapy, anti-inflammation, hypocholesterolemic activity, anti-obesity and immunomodulation. These effects are believed to be due to its unique structure that includes a putative helical region, an Arg-Gly-Asp (RGD) motif and an Asp-rich carboxyl terminus. The focus of this article is to summarize the discovery, characterization and biological activities of lunasin, which will provide a reference for the future development and utilization of lunasin, and a basis for exploring the underlying mechanisms of these health-beneficial functions.