A mobile terminal for performing a chat using an instant messaging service, the mobile terminal comprising: a wireless communication unit configured to perform the chat with at least one chat party using the instant messaging service; a display unit configured to display at least one chat window including a chat content display region and a chat content input region while the chat with the at least one chat party is ongoing, wherein the chat content display region displays at least one message previously transmitted to the at least one chat party and the chat content input region displays at least one new message that is to be transmitted to the at least one chat party; and a controller configured to: control the wireless communication unit to perform the chat with a first chat party and control the display unit to display a first chat window when the first chat party is selected, and control the wireless communication unit to perform the chat with a second chat party when the second chat party is selected and control the display unit to display at least one specific message transmitted during the chat with the first chat party in the chat content input region, wherein the controller is further configured to control the display unit to edit the at least one specific message transmitted during the chat with the first chat party that is displayed in the chat content input region when an editing function is selected. a wireless communication unit configured to perform the chat with at least one chat party using the instant messaging service; a display unit configured to display at least one chat window including a chat content display region and a chat content input region while the chat with the at least one chat party is ongoing, wherein the chat content display region displays at least one message previously transmitted to the at least one chat party and the chat content input region displays at least one new message that is to be transmitted to the at least one chat party; and a controller configured to: control the wireless communication unit to perform the chat with a first chat party and control the display unit to display a first chat window when the first chat party is selected, and control the wireless communication unit to perform the chat with a second chat party when the second chat party is selected and control the display unit to display at least one specific message transmitted during the chat with the first chat party in the chat content input region, control the wireless communication unit to perform the chat with a first chat party and control the display unit to display a first chat window when the first chat party is selected, and control the wireless communication unit to perform the chat with a second chat party when the second chat party is selected and control the display unit to display at least one specific message transmitted during the chat with the first chat party in the chat content input region, wherein the controller is further configured to control the display unit to edit the at least one specific message transmitted during the chat with the first chat party that is displayed in the chat content input region when an editing function is selected.