Jaw tremor in Parkinson's disease (PD) may not respond well to conventional treatment. It causes embarrassment and social handicap. We piloted the use of botulinum toxin (BTX) injections in three patients with PD jaw tremor. BTX A (Dysport; mean, 53 U; range, 30-100 U) was given into each masseter muscle. Outcome was assessed by subjective and clinical improvement and by video recording before and 4 to 9 weeks after injections. There was an excellent response in all without side effects. BTX injections into the masseter may effectively improve jaw tremor and be useful in PD and other conditions.