A double-blind trial of propranolol, in a dosage of 120 mg a day, and placebo was conducted in 11 patients with essential tremor. An improvement in tremor was observed in all patients who received propranolol and was most pronounced in the upper extremities. The favorable clinical assessment was further confirmed by improvement in a grooved pegboard test and in the quality of handwriting as evaluated by two "blind" observers. No side effects were encountered. It is concluded that propranolol is at present the best available drug for the treatment of essential tremor.