Recent studies have revealed autonomic dysfunction in amyotrophic lateral sclerosis (ALS). We studied salivary gland function by quantitative scintigraphy in ALS patients (n = 30) and healthy controls (n = 30). Uptake of (99m)Tc-pertechnetate in the parotid and submandibular glands was significantly decreased in ALS patients. No correlation was found between radiotracer uptake and regions of onset (bulbar-limb), duration of disease, or functional scores. Our data show early subclinical autonomic involvement supporting the view that ALS is a multisystem degenerative disease.