A case of postural hypotension in a patient with tabes dorsalis is reported. A polygraphic study of the arterial pression by intraortic catheterism, laboratory examinations and Minor test were made. As the results were negative for a disorder in the autonomic nervous system, it was concluded that the lesion responsable for the postural hypotension in the reported case was localizated in the aferent system of the baroreceptors.