Laryngeal keratosis is not common but well-known premalignant lesion. Unfortunately there is no generally accepted single histologic classification for laryngeal keratosis. Histologically atypia is important finding because the tendency for keratosis to develop into invasive carcinoma increases with the degree of atypia. The authors investigated the change of glycoproteins using seven kinds of lectins in laryngeal keratosis with or without atypia. Cell membranes in prickle layer were positive and cytoplasm of prickle cells were negative for WGA, RCA-I, UEA-I, SBA and PNA in laryngeal keratosis without atypia. On the other hand, cell membranes in prickle layer were negative and cytoplasm of prickle cells were positive for them in cases of laryngeal keratosis with atypia. These observations suggest that lectin histochemical staining with WGA, RCA-I, UEA-I SBA and PNA can be useful in detecting laryngeal keratosis with atypia.