Progressive limb dystonia contributed to disability in 8 of 30 patients with progressive supranuclear palsy (PSP). In five, it was present when the patients were on no medication. In four, it had been present before the distinctive ophthalmoplegia permitted a correct diagnosis. The severity of limb dystonia did not correlate with the severity of either ophthalmoplegia or neck dystonia. The importance of dystonia in the pathophysiology of PSP is emphasized, with regard to both the branchial dystonia that underlies several cardinal features of the disease, and to the frequent occurrence of limb dystonia as an early sign.