Narrow band imaging (NBI) is a new endoscopic technique in which images of mucosal microstructures and capillary structures are enhanced by shifting the light spectrum to a narrow band. Image-enhanced gastrointestinal endoscopy using NBI has improved the qualitative diagnosis of the grade and depth of invasion of an atypical lesion. NBI is currently not commonly used in gynecological endoscopy, but has recently been applied in laparoscopy and hysteroscopy. The utility of NBI for diagnosis of endometrial lesions and endometriosis has also been shown. In gynecological endoscopy, NBI provides enhanced images of mucosal microstructures and capillary structures and improves visual identification of lesions. Therefore, image-enhanced observation using NBI is likely to be useful for improved detection of lesions in endoscopic diagnosis. However, this technique remains experimental so far, and no study has demonstrated improved clinical outcome using this technique. In this review, we discuss the utility and potential applications of NBI in clinical practice in gynecology.