A computer system including one or more processors and persistent, word-addressable memory implements a persistent atomic multi-word compare-and-swap operation. On entry, a list of persistent memory locations of words to be updated, respective expected current values contained the persistent memory locations and respective new values to write to the persistent memory locations are provided. The operation atomically performs the process of comparing the existing contents of the persistent memory locations to the respective current values and, should they match, updating the persistent memory locations with the new values and returning a successful status. Should any of the contents of the persistent memory locations not match a respective current value, the operation returns a failed status. The operation is performed such that the system can recover from any failure or interruption by restoring the list of persistent memory locations.