When detected early, uterine cervical cancer is one of the most successfully treatable forms of cancer. The diagnostic accuracy of the standard method, the Pap smear test followed by colposcopy, remains unsatisfactory. To improve detection of early-stage cervical cancer, new diagnostic tools for uterine cervical intraepithelial neoplasm (CIN) need to be developed. Magnifying endoscopy with narrow- band imaging (ME-NBI), which allows the visualization of the micro-structure as well as micro-vascularity of the mucosal surface, has excellent diagnostic ability for early gastrointestinal neoplasms. In our previous investigation, ME-NBI was efficacious for diagnosis of CIN. We herein report two notable cases of CIN3 that were diagnosed by ME-NBI that were not detected by colposcopy. These cases illustrate the usefulness of ME-NBI for diagnosis of early-stage uterine cervical neoplasms.