The first results of a collaborative study aimed at collecting all French families affected by oculopharyngeal muscular dystrophy (OPMD) and their genealogy are presented. The study was carried out in 28 families in whom the diagnosis of OPMD in the propositus was confirmed by the presence of typical intranuclear tubulo-filamentous inclusions in the muscle biopsy. Results suggest that the prevalence of OPMD in France is at least of 1/200,000. The disease has been observed in many countries but to our knowledge no epidemiological studies have been reported so far. However, it is known to be particularly frequent in the French-Canadian community living in Canada and USA. In the present study genealogical researches were carried out in 18 families. Three families were of Italian and two of Armenian origin. Amongst the 13 families of French ascent, 3 familial relationships were found: one from a couple married in 1783. In the other 10 French families, no interlineage was discovered in a genealogical enquiry pursued back to the 18th century. Further studies are needed to find out whether there was only one mutation responsible for all French cases or whether several mutations occurred in France, as suggested by the present study. It would be also interesting to ascertain whether there is a parental link between the French and the French-Canadian OPMD patients, the latter considered to be descendants of a couple who emigrated to Quebec in 1634.