Nasal polyps are generally considered as a result of extreme nasal mucosal edema induced by long-term recurrent inflammation of the respiratory mucosa. The estradiol (E2) has been demonstrated to play a facilitating role in nasal inflammation. To evaluate the effect of estradiol on the pathogenesis of nasal polyps, the expression of E2 receptors in paraffin section from patients with nasal polyps (84 cases), chronic hypertrophic rhinitis (6 cases) and healthy control subjects were investigated by means of immunohistochemistry for E2 receptors and toluidine blue staining for mast cells. It was shown that there was high expression of E2 receptors in 61 out of 84 cases (male 40, female 44) of nasal polyps and the expression distributed equally among both sexes. Low expression of E2 receptors presents in 2 out of 6 cases of chronic rhinitis and 1 out of 4 healthy subjects. Noteworthily, the E2 receptor expressing cells are similar with the mast cells in shape and distribution. The authors speculate that they may be identical cells. E2 receptor expression in nasal polyps suggests that estradiol plays certain role in the development of nasal polyps.