Suction rectal biopsy with acetylcholinesterase (AChE) histochemistry has been recognized as a reliable method for the diagnosis of Hirschsprung’s disease (HD). This study compares the final pathologic diagnosis made on paraffin embedded material of 68 colectomy specimens with the histochemical AChE reaction from the same patients previously diagnosed as HD by rectal suction biopsy at the Hospital Infantil Pequeno Principe (Curitiba, Brazil) from 1988 to 1999. The group included 58 male and ten female patients with ages ranging from 7 days to 10 years. Thirty-six patients (52.94%) where under 1 year of age at time of surgery. Two of the 68 patients had previous normal histochemical reactions for AChE: one of them resulted a normal ganglionic segment of bowel and the other one was a 15-day-old boy with total colonic aganglionosis, the only false-negative result in this series. Two patients had inconclusive results and because untreatable clinical symptoms also received surgical treatment. One of them resulted a normal ganglionic bowel and the other one was diagnosed as HD. All surgical specimens from the other 64 patients resulted in various extents of aganglionosis presenting prominent nerve trunks in the submucosal and myenteric plexuses, confirming the previous AChE histochemical diagnosis. In three cases there was total colonic aganglionosis. In this study the rectal suction biopsy associated with the histochemical method of AChE, performed days, months or sometimes years before surgery, resulted in a diagnostic accuracy rate of 95.59%, a positive predictive value of 100% and there were no false-positive results.