A self-repair method intervenes at the end of an operation of modification of a nonvolatile memory, selected between programming and erasing, in the event of detection of just one non-functioning cell, and carries out redundancy of the non-functioning cell. To this end, the memory array is divided into a basic portion, formed by a plurality of memory cells storing basic data, and into an in-the-field redundancy portion. The in-the-field redundancy portion is designed to store redundancy data that include a correct content of the non-functioning cell, the address of the non-functioning cell, and an activated redundancy flag. The redundancy is activated only after applying a preset maximum number of modification pulses and uses a redundancy replacement circuit and a redundancy data verification circuit.