As an emerging functional food ingredient, resistant starch has been shown to have equivalent and/or superior impacts on human health similar to conventional fiber. Resistant starch has been introduced to human nutrition and the food industry in recent years as an increasingly important functional food ingredient. Unlike some carbohydrates and digestible starches, resistant starch resists enzymatic hydrolysis in the upper gastrointestinal tract, resulting in little or no direct glucose absorption. In addition, there is increased microbial fermentation production of short-chain fatty acids (SCFAs) in the large intestine, a typical phenomenon of fiber consumption.Resistant starch content in foods could be altered by selecting plant sources and modifying the processing conditions of starch-based foods. Resistant starch can be measured in vitro using several methods including the Englyst method and the Association of Official Analytical Chemists (AOAC)/American Association of Cereal Chemists International (AACC-I) standard method. In this article, the definition and classification of resistant starch, including some potential health benefits, strategies to enhance resistant starch in starch and starch-based food, and determination of resistant starch in starch and food, are discussed and updated.