The diagnosis of Hirschsprung's disease relies upon histology and acetylcholinesterase histochemistry of the enteric neural plexi. A distinctive neurofilament protein staining pattern has been claimed in Hirschsprung's disease. We studied 10 colons affected by Hirschsprung's disease, together with appropriate controls using antibodies to neurofilament protein (NFP; monoclonal), neurone-specific enolase (NSE), glial fibrillary acidic protein (GFAP) and S-100 protein (all polyclonal), and conventional histology and histochemistry, seeking an immunohistochemical diagnostic method. We found staining for NFP, NSE and S-100 protein of many of the nerve fibres and satellite cells in the enteric plexi, but without significant differences between affected and unaffected colons. Staining for GFAP was weakly positive in a minority of cases and controls and the majority of neurones in control sections stained for NSE. In contrast to acetylcholinesterase little staining was localized in the lamina propria. Staining for NSE and S-100 is useful in identifying immature ganglion cells in paediatric large intestine.