We describe a family with autosomal dominant progressive supranuclear palsy (PSP) involving five generations which was confirmed in one patient. The proband presented with progressive slowness at age 53 years, followed by ocular palsy, loss of balance, axial dystonia, dysphagia and dysarthria, and died at age 59 years. Neuropathological examination revealed moderate numbers of neurofibrillary tangles without prominent senile plaques in the cortex, and neuronal loss, gliosis and moderate to severe accumulation of tangles in the basal ganglia and brainstem. Other affected relatives, including the proband's sister, father, paternal uncle, and other members of earlier generations presented with non-characteristic akinetic syndromes, which progressed towards more typical PSP only after several years of disease. A review of the literature revealed six other families with neurodegenerative disorders associated with pathological findings compatible with PSP in at least one member. The clinical symptoms varied greatly between individuals in these families. The pattern of inheritance seems compatible with autosomal dominant transmission, although other patterns of transmission could not be excluded. We conclude that there is an autosomal dominant form of PSP and that the number of hereditary cases may be greater than previously thought. The rarity of familial cases of PSP could be attributed to diagnostic problems, including lack of recognition of atypical cases and death of the gene carriers before the age of appearance of the clinical symptoms. Large families with hereditary PSP could provide an adequate point of departure for investigation of the gene defect responsible for this disease.