Objective. To analyze complications of intrathecal baclofen therapy and identify high-risk groups. Material and methods. We implanted 52 pumps to spastic patients for chronic intrathecal baclofen infusion. Two groups of patients were distinguished: 23 patients with spinal spasticity (group 1) and 29 patients with cerebral spasticity (group 2). The mean patient age was 37.2±14.6 years in group 1 and 17.3±10.3 years in group 2. Surgery was performed according to a standard procedure. A Medstream (Codman) pump was implanted in 10 cases, and a Synchromed II (Medtronic) pump was implanted in the remaining 42 cases. Results and discussion. Complications developed in 12 (23%) patients. We divided complications into 3 groups: baclofen underdose, baclofen overdose, and others. Insufficiency of intrathecal therapy was observed in 7 cases, which was caused by catheter migration (5 cases) and pump dysfunction (2 cases). In one case, baclofen overdose was observed after air travel. Other complications included 4 cases of persistent peri-implant seroma and infectious complications. Groups with a high risk of complications were identified based on an analysis of the results. Patients with severe dystonia of the trunk muscles have an increased risk of spinal catheter migration. Pronounced communicating hydrocephalus is associated with the risk of cerebrospinal fluid leak through a catheter shaft channel. Weakness of the axial musculature can lead to progression of scoliotic deformity. Conclusion. In some cases, chronic intrathecal baclofen therapy can be accompanied by various complications. This technique should be carefully used in patients from high-risk groups.