A system for providing billing information of a wireless data communication service includes an Inter-Working function (IWF) for, if a data call is received, assigning an Internet protocol (IP) address to a mobile communication terminal that has sent the data call and transmitting the assigned IP address to a billing server; the billing server for, if the IP address is received, searching for billing information related to the mobile communication terminal from among stored billing information, inserting the found billing information into a ping message, and transmitting the ping message to the mobile communication terminal; and the mobile communication terminal for sending the data call, receiving the assigned IP address, performing wireless data communication using the assigned IP, transmitting a ping response message to the billing server if a ping message is received from the billing server, determining whether the ping message contains billing information, and displaying the billing information contained in the ping message if it is determined that the ping message contains billing information.