Six clinico-pathological cases (4 males and 2 females) with a Parkinson-like syndrome which lasted an average of 5 1/2 years are reported. The average age at death was 73 years. Neuropathological features were similar to those described in post encephalitic Parkinson's syndrome and in Steele-Richardson-Olszewski disease. However, neurofibrillary tangles were less numerous; lesions in tectal, periaqueductal and reticular structures were less severe. Furthermore, the lesions seemed more pronounced in the substantia nigra, the globus pallidus and the nucleus subthalamicus, giving the appearance of a systematic pallido-luyso-nigral atrophy. None of these patients had a history of encephalitis. Clinical examination did not reveal the dystonic rigidity in extension of the neck nor the characteristic ophthalmoplegia of progressive supranuclear palsy. These 6 cases are compared to 10 cases of progressive supranuclear palsy typical both on clinical and pathological grounds. They could be considered as a particular form of Steele-Richardson-Olszewski disease without ophthalmoplegia.