OBJECTIVE To evaluate the reliability of the Ashworth Scale and the Disability Assessment Scale (DAS) in poststroke patients with upper-limb spasticity and functional disability. DESIGN Single-center trial. SETTING University medical center. PARTICIPANTS Nine patients > or = 6 months poststroke with upper-limb spasticity and impairment in the areas of hygiene, dressing, limb posture, or pain were included in the analysis. INTERVENTIONS Ten experienced medical professionals rated each patient in randomized order twice on the same day (results based on mean of evaluations at times 1 and 2). Elbow, wrist, finger, and thumb flexion tones were assessed by using the Ashworth score (range, 0-4), and functional disability was assessed using the DAS (range, 0-3). MAIN OUTCOME MEASURES Intra- and interrater reliability of the Ashworth Scale and DAS. RESULTS For the Ashworth parameters, 38 of 40 evaluations indicated excellent (weighted kappa > or = .75) or good (weighted kappa > or = .4) intrarater reliability. For DAS parameters, 31 of 40 evaluations indicated excellent or good intrarater reliability. The interrater reliability was also good for both the Ashworth Scale (Kendall W=.598-.792) and DAS (Kendall W=.494-.772) with statistically significant agreement found among raters (all P<.001). CONCLUSIONS In patients with upper-limb spasticity after stroke, the Ashworth Scale and DAS had good intra- and interrater reliability when used by trained medical professions.