To determine what governs nitric oxide (NO) yields of cigarettes and to obtain a range of yields for contemporary cigarettes 17 UK, 14 US, 8 French and 1 Turkish brand were analysed using a chemiluminescent analyser and standard smoking machine. The country of origin appeared to be the major factor affecting NO yield. US and French brands exceeded UK values by 3–5 fold. Apart from a reduced NO yield in UK ventilated filtered brands, the design of a cigarette and its tar, nicotine and carbon monoxide (CO) yield had little effect on NO yield. It is argued that these international differences in NO yields reflect differences in the nitrate content of tobaccos traditionally used in manufacture in those countries over many years. Despite their probable increased lifetime exposure to NO (and by implication nitrosamine exposure) there appears to be little evidence that US and French smokers are at greater risk of lung disease than their UK counterparts.