An apparatus and method for transmitting/receiving multicast data in a wireless communication system are disclosed. The method of receiving multicast data at a machine-to-machine (M2M) device in a wireless communication system includes: receiving, from a base station (BS), an M2M multicast connection identifier for an M2M multicast service, assigned to the M2M device; receiving a message including control information about transmission of the multicast data and multicast data including an M2M multicast connection identifier from the BS; and determining whether the M2M multicast connection identifier included in the multicast data corresponds to the M2M multicast connection identifier assigned by the BS.