Abstract Background Recent studies increasingly utilize the Movement Disorders Society Sponsored Unified Parkinson's Disease Rating Scale (MDS-UPDRS). However, the minimal clinically important difference (MCID) has not been fully established for MDS-UPDRS yet. Objective To assess the MCID thresholds for MDS-UPDRS Motor Examination (Part III). Methods 728 paired investigations of 260 patients were included. At each visit both MDS-UPDRS and Clinician-reported Global Impression–Improvement (CGI-I) scales were assessed. MDS-UPDRS Motor Examination (ME) score changes associated with CGI-I score 4 (no change) were compared with MDS-UPDRS ME score changes associated with CGI-I score 3 (minimal improvement) and CGI-I score 5 (minimal worsening). Both anchor- and distribution-based techniques were utilized to determine the magnitude of MCID. Results The MCID estimates for MDS-UPDRS ME were asymmetric: −3.25 points for detecting minimal, but clinically pertinent, improvement and 4.63 points for observing minimal, but clinically pertinent, worsening. Conclusions MCID is the smallest change of scores that are clinically meaningful to patients. These MCID estimates may allow the judgement of a numeric change in MDS-UPDRS ME on its clinical importance.