Abstract: There is described a method of optimizing a mail sorting process having a first and at least a second sorting cycle performed in succession on a sorting machine, which receives a group of mail items at an input and supplies, at its outputs, the mail items identified and separated according to given sorting rules; in a given sorting cycle, the mail items being fed to the outputs of the machine according to a predetermined respective sorting criterion, and then being fed in orderly manner back into the input of the machine for a following sorting cycle; each output of the sorting machine being assigned at least one respective delivery location according to an assignment criterion related to the delivery order of the mail items in the delivery locations.