Flexible fiberoptic colonoscopy is an established diagnostic procedure in the pediatric patient. The approach to the pediatric patient is, however, different from the approach to adults. Bowel preparation must be geared to the age, size, and clinical status of the patient. An effective, palatable, standardized bowel preparation has not been determined for the child undergoing a colonoscopy. This study systematically evaluated three components of the bowel preparation--cathartics, diet, and enema use. The bowel preparation of 140 children undergoing colonoscopy at The Children's Hospital of Philadelphia was evaluated. The effectiveness of the bowel preparation was evaluated by direct visualization during the colonoscopy as to the amount and consistency of the residual stool in the colon. Parents were interviewed to determine adherence to the instructions including tolerance of diet, cathartics, and enema administration. Equipment maintenance was also monitored. An effective bowel preparation was achieved in all groups. As a result of this study, the Division of Gastroenterology and Nutrition at The Children's Hospital of Philadelphia now uses a less restrictive diet, one enema, and X-Prep to achieve effective bowel preparation for colonoscopy.