Background: The conventional classification of the degree of hemorrhoids does not consider the severity of hemorrhage. The purpose of this study was to establish a new objective method for evaluating hemorrhoids in close relation to the main symptoms, hemorrhage and prolapse, as observed through a retroflexed colonoscope in the rectum. Methods: The subjects were 531 consecutive patients who complained of symptoms related to the rectum or the anus. The degree of mucosal elevation of the rectal columns, changes in color (the existence and degree of red color sign, dilated vein, and white area), and the existence and size of hypertrophied anal papillae were evaluated by colonoscopy. Results: Red color sign was the finding closely related to hemorrhage (p < 0.0001). Dilated vein, white area, and a large hypertrophied anal papilla were related to prolapse (p < 0.0001). The degree of mucosal elevation of the rectal columns was related to both hemorrhage and prolapse (p < 0.0005, p < 0.05). Conclusion: Retroflexing the colonoscope intrarectally facilitated identification of findings in the anal canal related to hemorrhage and prolapse, which are the clinical manifestations of hemorrhoids. (Gastrointest Endosc 1998;48:272-5.)