Abstract: A locking device for simultaneously locking two adjacent file cabinet drawers in a cabinet housing includes a locking mechanism mounted on a front face of one drawer. When a key is turned to actuate the locking mechanism, a cam, attached to the locking mechanism and positioned generally horizontally in a chamber formed in the first drawer, is rotated through a slot formed in a wall of the first drawer. Continued rotation of the locking mechanism rotates the cam through a slot formed in a mullion provided between the first drawer and an adjacent second drawer and into a slot formed in the second drawer to a generally vertical position for the cam. A central portion of the cam cooperates with the mullion and an end portion of the cam cooperates with the slot in the second drawer to prevent movement of the two drawers in the housing.