A method for transmitting and receiving data in a wireless communication system, and a device therefor are disclosed. Particularly, a method for transmitting downlink data in a packet data network gateway (P-GW) in a wireless communication system can comprise the steps of: receiving, from an application server, downlink data in which an Internet protocol (IP) header including an IP address of a terminal is encapsulated; removing the IP header from the downlink data; and transmitting, to a serving gateway (S-GW), the downlink data from which the IP header is removed through a bearer identified by the IP address of the terminal, so as to transmit, to the terminal, the downlink data from which the IP header is removed.