[EN] Objective: To study effectiveness of and satisfaction with a virtual reality-based balance rehabilitation system (BioTrak) for patients with acquired brain injury (ABI). Material and methods: Ten patients with chronic hemiparesis (chronicity > 6 months) following an ABI completed a 20-session programme using the balance reaching-task module of the BioTrak system. All patients were assessed at baseline, at the end of treatment and one month later with the Berg Balance Scale (BBS), the Tinetti Performance-Oriented Mobility Assessment (POMA), and the computerised posturography tool NedSVE/IBV. The posturography study included analysis of sensory indexes, limits of stability and rhythmic weight shift. The usability study was conducted using an ad hoc questionnaire. Results: Repeated measures ANOVA showed a significant improvement in BBS (P < .01), TBS (P < .01), vestibular index (P < .05), and anterior-posterior weight shift (P < .05); a trend in the same direction was also found for medial lateral weight shift (P = .059). The post-hoc analysis revealed significant improvement between the initial and final assessments for BBS, POMA and anterior-posterior weight shift control; gains remained a month after completing the programme. The system showed a high degree of usability in terms of presence, immersion and user-friendliness, and there was a significant absence of adverse effects. Conclusion: Our results confirm the utility of virtual reality systems for balance rehabilitation in this population. Usability data suggest that BioTrak could be adapted for use in multiple rehabilitation settings by a high number of patients. © 2011 Sociedad Española de Neurología