The association between snoring and blood pressure is still a matter for debate, partly because of uncertainty about the definition of snoring and partly because confounding factors may affect systemic blood pressure such as obesity, sleep apnoea, and nocturnal hypoxaemia. To isolate the contribution of each of these factors, 1415 patients (389 females, 1026 males) referred to a sleep disorders centre were studied. A full history was obtained with particular attention to cardiovascular disease and medications. The patients had nocturnal polysomnography including objective measurement of snoring, and blood pressure was measured in the morning. 18% of non-snores had hypertension as did 20% of heavy snores (not significantly different). Multivariate linear regression analysis showed that snoring was not a significant determinant of blood pressure. Only age, male sex, apnoea/hypopnoea index, and body mass index contributed significantly to the variability of blood pressure. We conclude that snoring in the absence of sleep apnoea is not associated with raised blood pressure.