This study was conducted to establish the concurrent validity and interrater reliability of the Motor Assessment Scale (MAS) for stroke patients. Thirty hemiplegic subjects were tested with the MAS and the Fugl-Meyer Assessment (FMA), a reliable and validated test of motor function in stroke patients. The high correlations obtained between the total scores on the MAS and the FMA (r = .88) and between specific item scores (except sitting balance) (r = .28 to .92) provide support for the concurrent validity of the MAS. Interrater reliability coefficients for the total MAS score and individual items on the MAS (except tone) were also high and significant.