A recent article published in the Journal of Pediatric Gastroenterology and Nutrition reported that constipation accounts for 25% of all pediatric gastroenterology consultations and a majority of these of children suffer from functional constipation. It was stated that although most children do not require any diagnostic testing, an accurate instrumental assessment is usually recommended for children who fail to respond to conventional medical treatment or present with a more significant clinical scenario. Diagnostic investigations are essential to determine the underlying pathophysiologic mechanisms and possible organic etiology. This article also described the results of a review which analyzed the possible diagnostic investigations for severely constipated children, focusing on their actual indications and their utility in clinical practice. It was disclosed that in the recent past a number of advanced techniques to measure transit and motility have been developed from the updated knowledge of normal and abnormal colonic and anorectal motility in children.