Although insecticides are important tools for the control of disease vectors, their loss effectiveness and associated environmental problems have led to research aimed at discovering or designing new active principles. However, little is known about the physiological effects of new insecticides. Using histopathological techniques, this study elucidates the morphological changes that occur in the midgut of Aedes aegypti larvae after treatment with the metal complex [Cu(EDTA)]^2-. The midgut was the most heavily affected part of the larvae. Cell debris was found in the lumen of the digestive system, a sign of the total destruction of insect tissue, specifically the destructive vacuolization of columnar and regenerative intestinal cells. The apical surfaces of the columnar cells exhibited oriented projections into the lumen, suggesting that these cells are involved in apoptosis. These results are an important supplement to the analysis and development of larvicides based on metal complexes, and will facilitate the design of effective Aedes aegypti control strategies.