Purpose To investigate: (1) the interrater, and test-retest reliability of the coin rotation test (CRT) in people with Parkinson's Disease (PwPD); (2) the minimum detectable change in the CRT; (3) the concurrent and known-groups validity of the CRT; and (4) the cut-off times that best discriminate PwPD from healthy people and functionally dependent PwPD from functionally independent PwPD. Method Forty-eight PwPD and 33 healthy people were included. The CRT was administered with the nine-hole peg test, Movement Disorders Society Sponsored Unified Parkinson's Disease Rating Scale, Hoehn and Yahr Scale, Parkinson's Disease Questionnaire-8, and Schwab and England Scale. Results The CRT had excellent interrater and test-retest reliability. Minimal detectable changes were 5.96 and 8.23 s for the dominant and non-dominant hand, respectively. The CRT correlated with other outcome measures. Significant differences in the CRT times were found between PwPD and healthy people, and between functionally dependent PwPD and functionally independent PwPD. The cut-off times of 12.66 s on the dominant hand and 15.76 s on the non-dominant best discriminated PwPD from healthy people, while 22.99 s on the dominant hand and 23.48 s on the non-dominant best discriminated functionally dependent PwPD from functionally independent PwPD. Conclusions The CRT is a reliable, and clinically available tool for assessing manual dexterity in PwPD.