A method of sorting mailpieces into a sorting frame having sorting slots where, in a sorting pass, and in a memory of a monitoring/control unit with a display screen, recording digital images of mailpieces to be sorted, each image including a delivery address; on the basis of each digital image of a mailpiece, generating a sorting code identifying a sorting slot of the sorting frame, and, in the memory, organizing the mailpieces into virtual stacks of images, each virtual stack of images corresponding to a stack of mailpieces placed in a stack in a sorting slot of the sorting frame and the images in each virtual stack of images being sequenced in the same order as the mailpieces in said stack of mailpieces; and in a subsequent sorting pass, displaying on the screen the images and a sorting code of said mailpieces organized in a virtual stack.