Neuropathological examination of the gut in a patient with chronic idiopathic intestinal pseudoobstruction and temporal lobe epilepsy showed a degeneration of Auerbach's and of Meissner's plexus. The extent of generative changes increased in an aboral to oral direction. Neuronal degeneration was characterized by ballooning of the cytoplasm of the ganglial cells, by a hyperargyrophilia, a shortening and dilation of cell processes, and a progressive fragmentation and loss of axons. In rectal biopsies, a PAS-positive granular material was detected in the cytoplasm of ballooned ganglial cells. A severe peripheral neuropathy with fiber degeneration in the posterior columns and axonal lesions within ventral nerve roots and a more recent fiber degeneration in the lateral columns corresponding to the picture of subacute combined degeneration of the spinal cord and a symmetrical Ammon's horn sclerosis was present. This case of progressive intestinal neuronal degeneration of unknown origin is a newly described condition leading to chronic idiopathic intestinal pseudoobstruction.