Oculopharyngeal muscular dystrophy is a progressive, hereditary myopathy in which the levator palpebrae and the pharyngeal muscles are selectively involved. Progressive, usually symmetric blepharoptosis with or without dysphagia appears in the fifth decade. The high prevalence of this myopathy in Quebec stems from the immigration of a single couple from France in 1634, whose numerous descendants manifest its autosomal dominant heredity. We review our experience in 91 cases over 20 years. The ptosis was moderate in 83% of the cases at the time of surgery, and the average age was 65 years. Beard's surgical guidelines for correction of ptosis based on the degree of ptosis and residual levator function were applied directly in cases of primary intervention, with consistently satisfactory results. This is in contrast to other types of hereditary myopathic ptosis, in which the guidelines must be modified. The rate of recurrence of ptosis among patients followed for at least 9 years was 13%.