Objective: To investigate clinical efficacy and incidence of complications regarding intrathecal baclofen (ITB) therapy in children. Methods: Retrospective medical chart review of 15 paediatric patients with congenital brain injuries who underwent ITB implantation for treatment of severe spasticity between 2003 and 2009. Results: Compared to the preoperative state, ITB therapy significantly reduced spasticity of lower limbs with corresponding decrease of the modified Ashworth scale (p < 0.05), while baclofen dosage increased (p = 0.001). Cobb angle of patients with scoliosis prior to ITB therapy (n = 8) increased significantly (p < 0.05) during follow-up. Overall, 10 complications (nine device related and one accidental) were found in six patients (40%), mostly emerging within the first three years after implantation. Conclusion: Intrathecal baclofen is an effective therapy option for paediatric patients to significantly reduce spasticity of lower limbs. The high incidence of complications implicates the need for a close monitoring of the patients especially in the early post-operative period.