The role of ultrasound in imaging the gastrointestinal (GI) system continues to evolve. While computed tomography (CT) remains the primary method for imaging the abdominal cavity, cost considerations, radiation risks associated with CT, and improved ultrasound image quality continue to fuel the emergence of well-defined gastrointestinal tract ultrasound applications. The GI Tract: Anatomy & Physiology Module begins with a review of GI tract anatomy and physiology. The sonographic anatomy and characteristics of the GI tract, from the esophagus to the rectum, are described in detail. Optimal transducer selection, patient positioning, and techniques for sonographically evaluating the GI tract are discussed. The course concludes with imaging tips and pitfalls and a summary of salient teaching points.