Twelve patients with writer's cramp were treated with injections of botulinum toxin. The overactive muscles were identified by clinical observation of the subjects while they were writing. Repeated injections were given at 2-week intervals until the optimal response was obtained. Eleven patients reported some benefit, which was considered by seven to be significant. Eight of the 10 patients who had pain reported moderate to significant relief. Five patients had local complications, consisting of disabling weakness of target or neighbouring muscles. These preliminary results suggest that this treatment can be successfully applied to many patients with writer's cramp without performing complex electromyographic recordings while the patients are writing.