The move comes after the 1935 landmark was heralded as a 'heroic example of Modernism' by the Twentieth Century Society (C20).
The department store, labelled 'reminiscent of Mendelsohn' by Pevsner, was designed by the architect when he worked in-house for the Co-op.
C20 describes the building as 'inspired by Erich Mendelsohn's designs for department stores on the continent', with the structure boasting 'dynamic horizontal window bands' and 'dramatic glazed stair towers'.
A C20 spokesperson said it hoped the building's listing would help ensure its future.
This is the second time in the last month that a landmark 20th-century building has been listed.
DCMS gave the green light to protect Lyons Israel and Ellis' 1958 former Old Vic workshops on London's The Cut in March.