Acute abdominal pain can represent a spectrum of conditions from benign and self-limited disease to surgical emergencies. Evaluating abdominal pain requires an approach that relies on the likelihood of disease, patient history, physical examination, laboratory tests, and imaging studies. The location of pain is a useful starting point and will guide further evaluation. For example, right lower quadrant pain strongly suggests appendicitis. Certain elements of the history and physical examination are helpful (e.g., constipation and abdominal distension strongly suggest bowel obstruction), whereas others are of little value (e.g., anorexia has little predictive value for appendicitis). The American College of Radiology has recommended different imaging studies for assessing abdominal pain based on pain location. Ultrasonography is recommended to assess right upper quadrant pain, and computed tomography is recommended for right and left lower quadrant pain. It is also important to consider special populations such as women, who are at risk of genitourinary disease, which may cause abdominal pain; and the elderly, who may present with atypical symptoms of a disease.