Patients, physicians, and health care providers want assurances that individuals performing gastrointestinal endoscopic procedures are competent and adequately credentialed. Definition of competence, however, has been an elusive goal. Most organizations, including professional societies and hospital privileging committees, have relied on estimated numbers of procedures performed or subjective assessment by a proctor as a surrogate marker of competence. Increasingly, objective assessment of performance is recognized as important in determining competence. Recent data have shown that learning curves for trainees are substantially more gradual than generally thought, and that the number of procedures required to achieve basic technical proficiency is much higher. Emerging data demonstrate that there is substantial variation in outcomes of endoscopy in clinical practice, related in part to the prior training, subspecialty background, ongoing case volume, and the individual endoscopist. Outcome variations correlate with both technical success and complications. Strategies for assessing competence in trainees and those in practice include numbers of procedures performed, subjective or objective assessment by a proctor, and self-assessment by the trainee. In the future, it is hoped that computers will be increasingly used to document outcomes of endoscopy in training and clinical practice as a part of routine report generation.