With a global annual production of more than 130 million tons, starch is one of the most used food ingredients due to its diverse functionalities. Starch granules are composed of amylose and amylopectin molecules, and the content and the arrangement of both molecules in the starch granules are known to impact starch usability in foods. Native starches do not always possess appropriate physical, chemical, and rheological properties for certain types of applications. This is why some key structural properties of starch can be modified in order to functionalize it and meet specific requirements. The four basic types of starch modifications are the chemical, physical, enzymatic, and genetic modification. In the present chapter, the starch molecular structure and the physicochemical and rheological attributes to be considered in starches when looking for food applications are presented. An overview of starch modification methods is given. The starch digestibility, the starch usage as a fiber substitute, the production of pregelatinized starches for baby food, and the starch application in food packaging are discussed.