OBJECTIVE To compare the gross and microscopic appearance of antrochoanal polyps associated with recurrent epistaxis, with those with a more typical presentation. METHODS Prospective, controlled study. METHODS All patients underwent clinical and endoscopic examination, computed tomography scanning, and examination under anaesthesia, in order to detect the gross diagnostic criteria for antrochoanal polyp. Histological findings on light microscopy were compared for polyps presenting with epistaxis versus those without. The number of predominant inflammatory cells in the corium was determined in both groups and statistically compared using the Student t-test. RESULTS Recurrent epistaxis was a presenting symptom in 10/84 (11.9 per cent) patients with gross diagnostic criteria for antrochoanal polyp. Grossly, these patients' polyps had a reddish, vascular surface in parts. Histologically, these polyps showed a highly vascular stroma with multiple dilated blood vessels, the typical appearance of an angiomatous antrochoanal polyp. Thrombi at different stages of development were detected, with no infarcts. The remaining cases (88.1 per cent) had no history of epistaxis; histologically, these patients' polyps showed an oedematous connective tissue core with few inflammatory cells. Plasma cells were predominant in the angiomatous polyps, being significantly more prevalent than in the ordinary antrochoanal polyps (p < 0.00). CONCLUSIONS It would appear that only angiomatous antrochoanal polyps present with epistaxis. Detection of the characteristic gross appearance of these polyps may help avoid unwanted surgery. Histopathological analysis confirms the diagnosis. A significantly increased number of plasma cells may be the underlying cause of the histological changes seen in angiomatous antrochoanal polyps.