In this study, the effects of different concentrations of carbohydrates on the phenoloxidase activity (PO) and development of Ephestia kuehniella larvae were investigated. For this purpose, 10 artificial diets-containing different carbonhydrates (sucrose or arabinose) were prepared. According to results, development and immunity are related to each other. A negative correlation was determined between the pupa mass, the amount of pupal lipid and the amount of pupal crude protein, and PO activity for all carbohydrate types. One of the remarkable results of the study is that the larvae fed on the 5A:P diet failed to reach the pupal stage. Diets-containing arabinose apart from 1A:P diet were consumed less than sucrose-containing diets. The PO activities of the larvae differ according to the dietary nutritional imbalance and the type of carbohydrates of diet. Except for 1A:3P and 1A:5P diets, the larvae fed on diets-containing arabinose generally have higher PO activities. The results show that arabinose is toxic to this species or that the carbohydrate is not usable by the larvae.