The natural history and response to different treatments have been evaluated in 264 patients with blepharospasm. The mean age of onset was 55.8 years and there was a female preponderance of 1.8 to 1. Dystonia elsewhere was found in 78% of patients, usually in the cranial-cervical region, and appeared to follow a somatotopic progression. A family history of blepharospasm or dystonia elsewhere was found in 9.5% of cases, which suggests a genetic predisposition. Ocular lesions preceded the onset of blepharospasm in 12.1% of cases. The response to drugs was inconsistent, although initial improvement was experienced by one fifth of patients treated with anticholinergics. Twenty-nine bilateral facial nerve avulsion operations were performed with benefit in 27 cases; but recurrences appeared in 22, on average one year after surgery. Botulinum toxin injections were performed in 151 patients. Significant improvement was achieved in 118 cases. Mean duration of benefit was 9.2 weeks. Transient ptosis and diplopia were the commonest side effects.