Disclosed is a proximity measurement method and apparatus for device-to-device (D2D) communication in a mobile communication system. The proximity measurement method may include determining whether a cell identification (ID) is included in a packet received from a gateway, verifying whether the cell ID matches a pre-stored cell ID when the cell ID is included, extracting, from the packet, Internet Protocol addresses of mobile terminals transmitting and receiving the packet when the cell ID matches the pre-stored cell ID, searching for IP addresses matched to the extracted IP addresses based on a proximity list including IP addresses of mobile terminals performing D2D communication, and registering, when the extracted IP addresses are absent in the proximity list, the extracted IP addresses in the proximity list and measuring proximity between the mobile terminals.