BACKGROUND: The new modified Melasma Area and Severity Index (mMASI) score, the recently used outcome measure for melasma, has not been tested to determine its sensitivity to change in melasma. OBJECTIVE: To determine the reliability, validity, and sensitivity to change overtime of the mMASI score in assessment of the severity of melasma. METHODS: Pearson correlation, Cronbach alpha, and intraclass correlation coefficient were calculated to assess the reliability of the mMASI score. Validity of the mMASI scale was carried out