Narrow-band imaging (NBI) is an image-enhanced form of endoscopy used to observed microstructures and capillaries of the mucosal epithelium that allows for real-time prediction of histologic features of colorectal polyps. However, NBI expertise is required to differentiate hyperplastic from neoplastic polyps with high levels of accuracy. We developed and tested a system of computer-aided diagnosis with a deep neural network (DNN-CAD) to analyze narrow-band images of diminutive colorectal polyps.