Cigarette smoking causes acute blood pressure (BP) elevation, although some studies have found similar or lower BPs in smokers compared with nonsmokers. Cross-sectional data from 3 years (1994 to 1996) of the annual Health Survey for England were used to investigate any difference in BP between smokers and nonsmokers in a nationally representative sample of adults (>/=16 years old). Randomly selected adults (33 860; 47% men) with valid body mass index (BMI) and BP measurements provided data on smoking status (never, past, or current) and were stratified into younger (16 to 44 years old) and older (>/=45 years old) age groups. Analyses provided between 89% and 94% power to detect a difference of 2 mm Hg systolic BP between smokers and nonsmokers in the 4 age/gender strata (alpha=0.05). Older male smokers had higher systolic BP adjusted for age, BMI, social class, and alcohol intake than did nonsmoking men. No such differences were seen among younger men or for diastolic blood pressure in either age group. Among women, light smokers (1 to 9 cigarettes/d) tended to have lower BPs than heavier smokers and never smokers, significantly so for diastolic BP. Among men, a significant interaction between BMI and the BP-smoking association was observed. In women, BP differences between nonsmokers and light smokers were most marked in those who did not drink alcohol. These data show that any independent chronic effect of smoking on BP is small. Differences between men and women in this association are likely to be due to complex interrelations among smoking, alcohol intake, and BMI.