The objective of this study was to assess the blood pressure pattern in patients with nasal polyposis. Twenty-seven patients with nasal polyposis (18 males and 9 females), ranging in age from 15 to 72 years (mean 37.1 years) were eligible for inclusion in the study. All patients were hospitalized overnight before surgery. After the basal blood pressure measurements were taken,: non-invasive ambulatory blood pressure monitoring was carried out. Oxygen saturation was measured via a finger probe and venous blood sampling was taken for catecholamine level during the full night.: All measurements were repeated 4 months after nasal surgery. Mean values for nocturnal decline in blood: pressure and heart rate before surgery were less marked than those measured after surgery. Mean decline values (+/- SD) were; 4.6 +/- 2.4 mmHg for systolic blood pressure, 5.8 +/- 3.8 mmHg for diastolic blood pressure, and 7.9 +/- 3.9 beats/min for heart rate before surgery, 9.3 +/- 2.8 mmHg, 8.5 +/- 4.1 mmHg and 10.4 +/- 4.3 beats/min after surgery (p < 0.01), respectively. Whereas mean and minimum SaO(2) (%) significantly increased (p < 0.01), catecholamine levels decreased (p < 0.05 for adrenaline, p < 0.01 for noradrenaline) after surgery. A correlation was found between BMI and blood pressure as well as between duration of obstruction and blood pressure. Patients who snored had higher blood pressure values than those who did not. Our data show that in cases of nasal polyposis, hypoxia, hypercapnia, snoring, and sleep disorders may develop and persons with nasal polyposis and snoring have an increased risk of hypertension and loss of nocturnal decline in blood pressure.