Acute appendicitis is the most common acute abdominal condition that results in surgical intervention in childhood. The clinical diagnosis of acute appendicitis in children can be challenging. Approximately one-third of children with the condition have atypical clinical findings and are initially managed nonoperatively. Complications associated with delayed diagnosis of this condition include perforation, abscess formation, peritonitis, sepsis, bowel obstruction, infertility, and death. The use of cross sectional imaging has proven useful for the evaluation of suspected acute appendicitis in children. Both graded compression sonography and CT have been widely utilized in the imaging assessment of the condition. The principal advantages of sonography are its lower cost, lack of ionizing radiation, and ability to assess ovarian pathology that can often mimic acute appendicitis in female patients. The principal advantages of CT include less operator dependency than sonography as reflected by a higher diagnostic accuracy, and enhanced delineation of disease extent in perforated appendicitis.