Objective. To estimate the efficacy of intrathecal treatment with baclofen (ITB) in spasticity and dystonia. Material and methods. Two groups of patients have been operated: 19 patients with spinal spasticity and 33 patients with cerebral spasticity (cerebral palsy). After baclofen screening test, the Synchromed2 (Medtronic) was implanted. The level of muscle tone was assessed by the Ashworth scale. The locomotion was assessed by GMFM 88 and Arens scale. The dystonia was assessed by the BFM scale. Follow-up was performed 3, 6 and 12 months after the operation and yearly after that. The duration of the follow-up ranged from 2 to 9 years. Results. ITB led to a significant decrease in leg spasticity in both groups of patients (p<0.001). The dynamics of spasticity was more significant in the first group compared to the second group (2.77 and 2.07 points, respectively (p<0.0031)). The dynamics of muscle tone in arms was lesser then in legs (p<0.0022). The positive clinical dynamics in patients with secondary dystonia was minimal (BFM from 65±17 to 60±19). Increasing of ITB daily dose was required to maintenance the clinical effect in most patients. The loss of ITB effect was noted in 5% of patients. Conclusion. ITB was more effective in patients with spinal spasticity. The influence of ITB on the secondary dystonia was lesser then on the spasticity. The dynamic of the muscle tone was more significant in legs than in arms. The loss of ITB effect can be observed in some cases after the operation despite the positive result of baclofen screening-test.