Estimates of cell loss in the intermediolateral columns of the thoracic cord in cases of progressive autonomic failure were made by counting nerve cells in the lateral grey horns from 21 such cases, and comparing (a) with "normal" controls, (b) with 3 cases of uncomplicated Parkinson's disease and (c) with 3 cases of multiple system atrophy without overt autonomic failure. It was found that all cases of autonomic failure had suffered severe cell loss; on average three quarters of their lateral horn cells were lost. The cases of uncomplicated Parkinson's disease did not differ from the controls; but the cases of multiple system atrophy without autonomic disturbances had lost about half their lateral horn cells. These findings are tabulated, and discussed.