• Intercostal muscle end-plates were measured in patients with amyotrophic lateral sclerosis (ALS) and more benign motor neuron disease (MND). The length of the intact end-plates in ALS and MND was not different from the controls. Segmented end-plates were increased in both ALS and benign MND, and the end-plate length was greatest in ALS. In individual ALS cases, no correlation was found between the end-plate abnormalities and relevant clinical variables.