A method writes data in a non-volatile memory comprising a main memory area comprising target locations, and an auxiliary memory area comprising auxiliary locations. The method comprises a write-erase cycle comprising: reading an initial set of data in a source location located in the main or auxiliary memory area; inserting the piece of data to be written into the initial set of data, to obtain an updated set of data, partially erasing a first group of auxiliary locations and a group of target locations designated by locations of a second group of auxiliary locations, and writing, in an erased auxiliary location of a third group of auxiliary locations, the updated set of data and the address of the target location. The method is particularly applicable to FLASH memories.