Cancer is one of the leading causes of death worldwide, generally exceeded only by cardiovascular disease in the developed world. The number of people diagnosed with cancer within the next few decades is expected to double. There will therefore be increased demand for novel diagnostic and medical therapies that use new non-traditional sources. Soybeans contain a variety of anticarcinogenic phytochemicals. Recently, there has been increased interest in the potential health benefits of bioactive polypeptides and proteins from soybeans, including lunasin and lectins. Lunasin is a polypeptide that arrests cell division and induces apoptosis in malignant cells. Lectins are glycoproteins that selectively bind carbohydrates; lectins are used in medicine in a variety of new applications. Additional research, including clinical trials, should continue to examine and elucidate the therapeutic effects, nutritional benefits, and toxic consequences of commonly ingested soybean lectins and lunasin.