Abstract: An interlocking device for drawers, especially for three or more drawers, comprises a plurality of units and each unit further comprises a channel, a base plate, two rotary blocks and a connecting bar. The channel is elongated with two bent lateral sides. The base plate is joined to an end of the channel. These two rotary blocks are oppositely disposed and rotatably fixed to the base plate. Each of rotary blocks is composed of a lower block part and an upper block part extending outward from the lower block part. The connecting bar at an end thereof rotatably engages with the rotary block, and the other end thereof rotatably engages with another rotary block on an adjacent unit. When one of these drawers is opened, slide rails at the outer side thereof move outward in the channel to push rotary blocks rotating outward. Thus, rotary blocks on other units rotate due to the movement of the connecting bar such that other drawers are prevented from slipping outward.