We applied immunohistochemical techniques to study alterations of the Golgi apparatus, and to determine possible relationships between this complex and the intraneuronal inclusions of lower motor neurons of patients with the sporadic form of amyotrophic lateral sclerosis (ALS). Spinal cords from normal individuals served as controls. Monoclonal antibodies to the Golgi zone and to Golgi beta-COP protein were used. Immunoreactivity with these antibodies was seen in frozen sections of paraformaldehyde-fixed spinal cord tissue, but not in formalin-fixed, paraffin-embedded specimens. The immunoreaction products were seen as granular structures, diffusely distributed in neurons and glial cells. Although immunostaining of some ALS neurons was reduced, fragmentation of the Golgi apparatus was not evident with either antibody. Bunina bodies and skein-like inclusions, characteristically found in spinal anterior horn cells of ALS patients, were not stained by these antibodies to epitopes of the Golgi apparatus, nor were Lewy body-like hyaline inclusions, present in some cases of sporadic ALS and reported to be characteristic to familial ALS with posterior column degeneration. These results suggest that components of the Golgi apparatus are not directly incorporated into intraneuronal inclusions. However, the possibility that abnormal proteinaceous material of the Golgi apparatus may be involved in their genesis cannot be ruled out.