It has been approved that the basophilic cells emigrate on the mucosal surface of nose and play an important role in the nasal manifestation of allergy.In this study, we counted the number of surface basophilic cells in 33 patients of chronic paranasal sinusitis with nasal polyps, in 18 patients of chronic paranasal sinusitis without nasal polyps and in 16 normal adults, and then the following results were obtained. 1) The basophilic cells were found in 5% of controls, in 11% of patients without nasal polyps and in 91% of patients with nasal polyps. (p<0.001) 2) In patients with the unilateral nasal polyps, the basophilic cells were increased only on the side with nasal polyps but not on the side without nasal polyp. There was a significant correlation between the positive basophilic cells and the presence of nasal polyps. (p<0.001) 3) Based on the results of allergic examination, the nasal polyps were classified into two types, i. e. allergic and non-allergic polyps. The majority of allergic polyps were bilateral and associated with a large number of basophilic cells. On the other hand, non-allergic polyps were mostly unilateral and had a small number of basophilic cells only on the side of polyp-formation. 4) The basophilic cells seemed to increase as a consequence of blockage of the airway but not as a cause of polyp-formation in non-allergic type.