Gastroenterology is the branch of medicine dealing with the digestive system and its disorders. This specialty focuses on diseases affecting the gastrointestinal tract, including the organs from mouth into anus, along the alimentary canal. To maintain a compliant and financially successful practice, gastroenterologists need to stay updated on the various coding guidelines and payer-specific protocols. Medical billing and coding for gastroenterology is challenging and requires an expert range of knowledge to ensure maximum reimbursement. These challenges include billing for colorectal cancer screenings vs. colonoscopies, motility, and GI function studies, documenting proper levels of evaluation and management services, category III codes for treatment of GERD, and applying the use of modifiers -51, -59, and -26.