This study will be a multicenter, randomized, prospective, parallel, double blind study that enrolls subjects at twelve sites (including Mt. Sinai) throughout the United States and Europe. The purpose of this study is to evaluate the safety and efficacy of BOTOX® compared to Zanaflex® in reducing upper limb muscle tone in post-stroke subjects, as well as evaluating changes in muscle tone-related disability and drug-therapy tolerance. This will be an 18 week study. Subjects are eligible if they have been medically stable with upper limb spasticity 6 months after their first stroke. Subjects will be randomized to one of three treatment groups: Treatment Group I - intramuscular BOTOX® plus oral placebo, Treatment Group II - intramuscular placebo plus oral Zanaflex®, Treatment Group III - intramuscular placebo plus oral placebo. The dose of BOTOX® will be at the discretion of the investigator with a maximum of 500 U per subject. The dose of the Zanaflex® will be 4mg/day to a maximum of 36mg/day. The study anticipates that 150 subjects will be enrolled to provide sufficient information to answer the primary objective of safety and efficacy of the study.