Advances in endoscopy simulation are reviewed with emphasis on applications in teaching and skills assessment. Endoscopy simulation has only been realized recently in a computer-based fashion because of advances in technology, but several studies have been performed both to validate computer-based endoscopy simulators and to assess their potential role in training. Multiple studies have shown that simulators can distinguish between clinicians at different skill levels and also have shown improvement in clinician skill, particularly at the early stages of training. This article summarizes those studies. The cost versus benefit of endoscopic simulators is also discussed, as well as the upcoming role of simulators in judging competence and as a tool in the credentialing process.