After the completion of the Human Genome Project, there has been an acceleration in methodologies on sequencing nucleic acids (DNA and RNA) at a high precision and with ever-decreasing turnaround time and cost. Collectively, these approaches are termed next-generation sequencing and are already affecting the transformation of medical practice. In this symposium article, we highlight the current knowledge of the genetics of selected gastrointestinal tract and liver diseases, namely, inflammatory bowel disease, hereditary cholestatic liver disease, and familial colon cancer syndromes. In addition, we provide a stepwise approach to use next-generation sequencing methodologies for clinical practice with the goal to improve the diagnosis as well as management of and/or therapy of the chosen digestive diseases. This early experience of applying next-generation sequencing in the practice of gastroenterology and hepatology will delineate future best practices in the field, ultimately for the benefit of our patients.