The invention provides methods of purifying rebaudioside A from a mixture comprising glycosides of the plant Stevia rebaudiana. The methods of the invention are useful for preparing highly pure rebaudioside A compositions from crude Stevia starting compositions that are typically considerably lower in rebaudioside A concentration. The highly pure rebaudioside A compositions are useful as non-caloric sweeteners in edible or chewable compositions such as food, beverages, medicine, candy, chewing gum, and the like.