Children and adolescents with chronic defecation disorders and chronic abdominal pain without obvious organic etiology form a challenging group of patients for pediatric health-care professionals. The pathophysiologic mechanisms underlying such functional gastroenterology disorders are poorly understood. Research studies on the use of the barostat have been aimed to increase our knowledge in this area. Barostat testing allows defining visceral hyper- or hyposensitivity, contractility, and compliance of the gut. This review focuses on rectal barostat studies performed in children with abdominal pain, constipation, and fecal incontinence.