The pathophysiologic mechanisms of blepharospasm are poorly understood and the condition is often misdiagnosed. In an attempt to improve our understanding of blepharospasm, 250 patients with blepharospasm were surveyed. This heretofore largest reported series of blepharospasm patients reveals findings of clinical and demographic interest. For example, there is a 3 to 1 female preponderance, the age of onset is in the fifth or sixth decade of life in two-thirds of patients, the onset is usually gradual with progressive deterioration and involuntary spasms of other portions of face and body. Although specific ocular abnormalities may predispose a patient to blepharospasm, in most cases the blepharospasm is a form of focal dystonia often associated with other involuntary movements and neurologic abnormalities. Increased awareness of blepharospasm among primary care physicians as well as ophthalmologists, neurologists, psychiatrists, and other specialists should lead to early recognition and management of this disabling condition.