Abstract: The treatment of store room walls, ceilings, floors and other structures is necessary as part of the good hygienic procedures recommended for reducing pests problems. Structural pests such as some moth species hide in the floor, corners, cracks and crevices inside machinery and are always difficult to control. With the continuous reduction of the availability of the insecticides, it is relevant to evaluate potential alternative methods of control. Habrobracon hebetor is a gregarious ectoparasitoid of pyralid moths that is found in large numbers in several food processing facilities in north-eastern Spain. H. hebetor can be a good candidate for biological control of moths that contaminate structures. In this work, we developed a banker box system for rearing H. hebetor on Ephestia kuehniella larvae and for releasing them progressively in the room. Different host-parasitoid ratios were tested to optimize the efficiency of the rearing box. Also, different apertures in the box were tested in order to allow the exit of adult parasitoids but avoid the larval moths to escape.