In 14 infants and small children the α-amylase activity and the carbohydrates of duodenal juice were studied after a test meal containing amylopectin. In infants at the end of the first year of life and in small children the amylopectin is very rapidly hydrolyzed into glucose, maltose, maltotriose, and branched dextrins; these compounds are probably hydrolyzed into glucose by the action of mucosal glucosidases. In infants 6 months old or younger the intestinal hydrolysis of amylopectin in the intestine is incomplete, with large amounts of dextrins containing more than 30 glucose units and, in the small oligosaccharides group, a decrease in the glucose and maltose content as well as an increase in the maltotetraose content. The analysis of carbohydrates which accumulate in intestinal lumen during digestion of starch will be of value in studying pathogenesis of starch malabsorption.