Autopsies in Japan are published annually. 633 autopsies with motor neuron disease and 236 with Parkinson''s disease are extracted along with control diseases, 550 with craniocervical injuries, 403 with myocardial infarction and 440 with pulmonary tuberculosis for 1964–1978. Accompanying diseases and pathological findings, excluding agonal and other irrelevant changes, were compared by sex and age in these conditions. Frequencies of the complications showed no practical difference from each of the control diseases to motor neuron disease and Parkinson''s disease in both sexes, indicating no association of the two diseases with other disorders recognizable at autops