Orthostatic hypotension syndromes may be associated with visceral denervation, resulting in disturbances of the gastrointestinal and urinary systems. This report analyzes the findings in 9 patients with neurogenic orthostatic hypotension and gastrointestinal symptoms. Antral and proximal small intestinal motor dysfunction was demonstrated in all patients: a significant reduction (p = 0.007) in the number of interdigestive motor complexes during 3 h of fasting (mean 0.4 vs. 1.3 controls); absence of gastric component in interdigestive motor complexes observed; incoordination of fasting and fed antral activity; and development of nonpropagating bursts of phase III-like activity in the intestine that were of at least 2-min duration, high amplitude and frequency, and associated with tonic elevations in baseline pressure. These motor abnormalities may provide a potential means for the diagnosis of impaired autonomic supply to the upper gut.