Two men, aged 57 and 77 years old, reported increasing unsteadiness on standing upright for the past 2 and 5 years, respectively. It had become impossible for them to remain standing for more than 10 seconds, as otherwise they might fall down. Walking, sitting and lying were possible without difficulty. Both patients were found to have a fine tremor in both legs on standing only. There were no other neurological signs or symptoms. Electromyography of the leg muscles demonstrated tremor activity at 14-16 Hz. Propranolol, 40 mg three times daily, in the 57-year-old patient brought no improvement. However, on taking primidone, in slowly increasing doses up to 250 and 500 mg daily, respectively, the condition lastingly improved in both patients.