During a 3-year period, 258 infants and children underwent rectal biopsy to exclude Hirschsprung's disease (HD) and related disorders; 32 (12%) were found to have HD. Major morbidity occurred in 3 (2%) of 148 patients undergoing rectal suction biopsy (RSB) and 22 (13%) of 168 suction biopsies were inadequate for diagnosis. In 102 children over 6 months of age, Storz rectal cup biopsy forceps were used with no significant morbidity and adequate biopsies were obtained in 96% of cases. Open rectal biopsy was performed in 8 patients. The RSB tube is safe and reliable, but attention to technique is important. For children over 6 months of age undergoing rectal biopsy for HD, the Storz rectal cup biopsy forceps yields superior results.