Study design: Double-blind, randomized, placebo-controlled, parallel-group clinical trial. Objective: Assess safety and efficacy of sustained-release fampridine in subjects with chronic spinal cord injury. Setting: A total of 11 academic rehabilitation research centers in the United States. Methods: A total of 91 subjects with motor-incomplete spinal cord injury (SCI), randomized to three arms: fampridine, sustained release, 25 mg b.i.d. (Group I), 40 mg b.i.d. (Group II), and placebo (Group III) for 8 weeks. Outcome measures: Patient diary questionnaire, Ashworth score, American Spinal Cord Injury Association International Standards, International Index of Erectile Function, bladder and bowel management questionnaires, and Clinician and Subject Global Impressions (Clinician Global Impression of change, Subject Global Impression (SGI)). Safety was evaluated from adverse events, physical examinations, vital signs, electrocardiograms, and laboratory tests. Results: In total, 78% of the subjects completed the study. More (13/30) discontinued from Group II than Group I (4/30) and Group III (3/31). The most frequent adverse events across groups were hypertonia, generalized spasm, insomnia, dizziness, asthenia, pain, constipation, and headache. One subject in Group II experienced a seizure. SGI changed significantly in favor of Group I (P=0.02). Subgroup analysis of subjects with baseline Ashworth scores >1 showed significant improvement in spasticity in Group I versus III (P=0.02). Conclusions: Group I showed significant improvement in SGI, and potential benefit on spasticity. The drug was well tolerated. Group II showed more adverse events and discontinuations. Sponsorship: The study was sponsored by Acorda Therapeutics, Inc. © 2007 International Spinal Cord Society All rights reserved.