A method of and apparatus for changing lesion classification data, the method including determining whether at least one mass is included in an image of an object, determining whether the at least one mass corresponds to a lesion by using first data including at least one first information, selecting a false negative (FN) mass which has been determined as not corresponding to the lesion among the at least one mass, based on a first input, and changing the first data to second data by using second information of the selected FN mass.