Objective: To investigate whether the direct application of vibratory stimuli inhibits spasticity and improves motor function in the hemiplegic upper limbs of post-stroke patients. Design: Prospective pilot study. Setting: University hospital rehabilitation centre. Subjects: Fourteen post-stroke patients (mean age = 57.3 years; SD = 19.1 years). Interventions: A hand and forearm stimulation device and an upper-arm stimulation device, consisting of vibrators, a wooden frame and a cloth strap, applied to the upper limbs of subjects. Main measures: The modified Ashworth scale (MAS) score, F-wave parameters and motor-function parameters (finger tapping, active range of motion and the simple test for evaluating hand function). Results: Subjects showed significant and potentially durable improvements in MAS score (p 0.01), F-wave parameters (p 0.01) and motor-function parameters (p 0.05). The MAS score, F-wave parameters and motor-function parameters dropped below the baseline values after vibratory stimulation. The MAS score and F-wave parameters remained significantly below the baseline 30 minutes after stimulation. Conclusions: The direct application of vibratory stimuli is an effective non-pharmacological anti-spastic treatment that could facilitate stroke rehabilitation. These results provide good evidence of potential short-term benefits of anti-spastic vibratory therapy in post-stroke patients in terms of decreased muscle tonus and improved motor function.