Provided are a method, system and program for effecting an operating system mode change from one mode to another. In one embodiment, the operating system in one mode is placed in a sleep state in which volatile memory remains active. In booting an operating system from the sleep state, a flag may be detected indicating an operating system mode transfer request. In response, contents of a selected range of volatile memory allocated to the first operating system mode may be swapped with the contents of a selected range of a reserve portion of volatile memory allocated to the second operating system mode. Booting of an operating system in the second mode may be completed using the swapped contents of the volatile memory. Additional embodiments are described and claimed.