Objective: To assess changes in body composition, body weight and resting metabolic rate in patients who received intrathecal baclofen therapy for spasticity. Design: Prospective, longitudinal, quasi-experimental, with a pre/post design. Patients: Twelve patients with spasticity, fulfilling study criteria, and due for pump implantation for intrathecal baclofen therapy, completed the study. Methods: Data were obtained before, 6 months and 12 months after commencement of intrathecal baclofen therapy as regards body composition (by skinfold calliper), body weight, and resting metabolic rate (by resting oxygen consumption). Spasticity was assessed according to the Modified Ashworth Scale (MAS) and Penn Spasm Frequency Scale (PSFS). Results: A reduction in spasticity according to MAS occurred. Mean fat body mass increased and mean lean body mass decreased. Mean body weight showed a non-significant increase and resting metabolic rate a non-significant decrease. Conclusion: This explorative study indicates that unfavourable changes in body composition might occur after intrathecal baclofen therapy. Since obesity and increased fat body mass contribute to an increased cardiovascular risk, these findings may indicate a need for initiation of countermeasures, e.g. increased physical activity and/or dietary measures, in conjunction with intrathecal baclofen therapy. Further studies, including larger study samples and control groups, are needed to corroborate these findings.