PURPOSE : A system and a method for performing a real estate mediation service between a customer and a licensed realtor through a messenger are provided to offer a correct/efficient consultation and service fit for a situation of the customer, as the telephone consultation is advanced after detecting a CID(Caller ID) of the customer and automatically search/loading customer information corresponding to the CID in a pop-up window.CONSTITUTION : A database(310) stores personal information of the customer, consultation information, and real estate article information. A CID detector(330) detects a telephone number of the customer connected through a communicator(320). A processor(340) automatically extracts the customer information corresponding to the detected telephone from the database, displays the extracted customer information, and operates a messenger program. An SMS(Short Message Service) server(370) transmits a text message or an image file, which is related to the real estate according to a consultation result, to the customer terminal(100). A realtor terminal(500) receives the customer information of the consulting customer through the messenger, and transmits the requested real estate information to a real estate mediation server(300).? KIPO 2006