Intramucosal ganglion cells are commonly believed not to occur in normal colon and to be found only in the chronic bowel motility disorder, neuronal intestinal dysplasia. After chance observations of two intramucosal ganglion cells in endoscopic biopsies in two patients without neuronal intestinal dysplasia, a retrospective study was undertaken to determine how frequently ganglion cells are present in colonic mucosa. Excluding the index cases, three intramucosal ganglion cells were found in 169 consecutive colonic biopsies. The nature of the ganglion cells was confirmed by positive neurone specific enolase staining by the peroxidase-antiperoxidase technique in all cases. None of the patients had neuronal intestinal dysplasia. The diagnosis of neuronal intestinal dysplasia should rely on a constellation of clinicopathological features. Rare intramucosal ganglion cells are a normal histological finding.