This review has the available information about the digestive physiology and morphology of three decapod species from Argentina: Pleoticus muelleri, Artemesia longinaris, and Neohelice granulata. The anatomy of the foregut may be modified in closely related species with similar feeding habits; however, the main features of the decapod crustacean digestive tract are similar to other species. Crustaceans express a set of highly active digestive enzymes that hydrolyze the major food items and include proteinases, lipases, esterases, and glucanases. The close relationship between diet and the range of digestive enzymes produced is well documented; however, digestive responses to specific nutrients differ widely among the species. Variations in digestive enzyme expression during early development reflect changes in digestive capabilities and can be used to identify early developmental feeding transitions. This information provides a deeper insight into nutrition, dietary preferences, and strategies of resource utilization, making possible the development of new aquacultural practices and providing data about the ecological niche that species occupy in aquatic systems. There is no doubt that the occurrence and activity of digestive enzymes are influenced by many internal and external factors, such as diet, molting, and development. The research of three Argentine decapod species is discussed in this review and provides a better understanding of basic digestive physiology. This information important to investigations of nutrition and feeding ecology of crustaceans.