The present invention relates to a mobile communication terminal that supports a text chatting function by using a short message service, and a text chatting service method. For this purpose, the present invention provides a mobile communication terminal including a program memory, a data storage unit, a key input unit, a display, and a microprocessor. The program memory stores a text chatting program for the text chatting service and a program that performs additional functions executed in the text chatting service. The data storage unit stores a text chatting message transmitted/received through the text chatting service. The key input unit includes a key button for generating the text chatting message. The display displays the transmitted/received text chatting message on a chatting window. The microprocessor executes the text chatting program and performs a control function to display text chatting messages communicated with a mobile communication terminal of a chatting contact on the chatting window. Herein, the text chatting message is transmitted/received by using a short message service. According to the present invention, a text chatting service using a short message service can be realized by simply changing a user interface of the mobile communication terminal so that a user can check a transmitted/received short message through one screen window, and provide a cost reduction by using a less expensive short message service than a data charge.