Betalains are plant derived natural pigments that are presently gaining popularity for use as natural colorants in the food industry. Although betalains from red beet are one of the most widely used food colorant, betalains are not as well studied as compared to other natural pigments such as anthocyanins, carotenoids, and chlorophylls. This chapter describes the chemical properties of betalains including their biosynthesis. Two main classes of betalains, betacyanins and betaxanthins, are described. Current reports on the biological and pharmacological properties of betalains from four main sources such as red beet, amaranth, prickly pear, and red pitahaya are also described. The biological and pharmacological properties of betalains that are covered in this chapter include antioxidant, anticancer, anti-lipidemic, and antimicrobial activities. Lastly, this chapter describes the application of betalains as natural colorants and other potential application in functional foods.