The work reported here was carried out to study the importance of immunocytochemical staining of neuron-specific enolase (NSE) in the diagnosis of Hirschsprung's disease and to compare its results with those obtained by hematoxylin-eosin (H&E) staining in consecutive sections. A retrospective study was made on 51 rectal mucosal biopsies and 19 colorectal surgical specimens from 52 patients clinically suspected of Hirschsprung's disease. Several consecutive sections from all cases were restained by H&E and for NSE demonstration. Sixteen (31%) patients had a histological diagnosis of Hirschsprung's disease, 9 (17%) had hypoganglionosis, 4 (8%) had neuronal intestinal dysplasia, and 2 (4%) had normal histology. In eight patients (15%) hypoganglionosis remained dubious, and in 10 (19%) the diagnosis was inconclusive. Although the NSE staining improved the identification of the nervous tissue of the colon, both H&E and NSE staining proved to be of equal value in the assessment of the presence of neurons in the rectal wall of people with clinically suspected cases of Hirschsprung's disease. Ten H&E-stained sections from different levels of the biopsy specimen would be enough to detect ganglion cells in most cases.