Programmed cell death (PCD) includes type I PCD apoptosis and type II PCD autophagy. Holometabolous insects, such as the fruitfly Drosophila melanogaster, have two types of organs:the endoreplicative organs (such as epidermis, salivary gland, midgut, fat body, malphigan and so on) and the mitotic organs (eyes, wings, legs, the nervous system and so on). During insect metamorphosis, endoreplicative organs undergo a complicated ‘remodeling’ process. The larval organs undergo apoptosis, autophagy, and eventually histolysis, whereas the adult progenitor cells give rise to the adult organs. However, the mitotic adult organs are directly formed from the larval organs. Throughout the process of insect metamorphosis, apoptosis and autophagy play an essential role in the formation of adult organs. In this paper, we will briefly introduce the physiological functions and molecular mechanisms of apoptosis and autophagy during insect metomorphosis.