The aim of this study was to investigate the effect of cigarette smoking on peripheral and central blood pressure (BP) in a group of young stage I hypertensives. A total of 344 untreated subjects from the HARVEST study were examined (mean age 37±10 years). Patients were divided into three groups based on smoking status: non-smokers, light smokers (⩽5 cigarettes/day) and moderate-to-heavy smokers (>5 cigarettes/day); and into three groups by age: 18–29, 30–39 and ⩾40 years. Central BP measurements and augmentation index (AIx) were calculated from brachial pressure waveform, with applanation tonometry, by means of the Specaway DAT System plus a Millar tonometer. The central waveform was derived from peripheral BP using the same software system of the SphygmoCor System pulse wave analysis. In addition, two indirect measurements of arterial stiffness were calculated: pulse pressure (PP) and systolic BP amplification. Central systolic BP and PP were higher in smokers than in non-smokers (systolic BP: 121.9±13.1 mmHg in non-smokers, 127.2±16.5 mmHg in light smokers, 126.7±15.3 mmHg in those who smoked >5 cigarettes/day, p=0.009; PP: 37.7±9.8 mmHg, 41.5±13.1 mmHg, 41.9±10.5 mmHg, respectively, p=0.005). Lower systolic BP amplification ( p<0.001) and PP amplification ( p=0.001) were observed in smokers compared to non-smokers. In a two-way ANCOVA analysis, systolic BP amplification markedly declined across the three age groups ( p=0.0002) and from non-smokers to smokers ( p=0.0001), with a significant interaction between smoking and age group ( p=0.05). The AIx was higher in smokers compared to non-smokers ( p=0.024). In young hypertensives, smoking has a detrimental effect on central BP, accelerating the age-related decline in BP amplification.