Abstract: Clinical scoring systems have been developed to risk-stratify patients who are presented to the emergency department with symptoms of acute appendicitis. They are used to rule out patients with acute appendicitis and those who may require imaging in the form of ultrasound or computerized tomography. The common scoring systems are the Alvarado score, RIPASA score, AIR, and AAS. In this chapter, we will look at the common clinical scoring systems that are used for adults and children. We will also look at the role of these scoring systems in diagnosing acute appendicitis and reducing the negative appendectomy rate.