Objective: Pulse pressure, a marker of arterial vascular properties, has been linked to cardiovascular diseases and complications. This study examined the impact of excess body mass and cardiovascular disease risk factors on pulse pressure(PP). Design: Cross-sectional and prospective study. Methods: Baseline data consist of 219 obese African Americans, with mean±SD age of 46.8±10.9 years enrolled in a diet and exercise program of weight reduction. A non-invasive monitoring device was used to acquire 24 hourly ambulatory blood pressures. Pulse pressure was calculated as the difference between the average 24-h systolic and diastolic blood pressure and studied as a continuous variable and according to quartiles. The cross-sectional association of pulse pressure with body mass index(BMI) was examined using multivariate linear regression and proportional odds models that controlled for cardiovascular disease risk factors. In addition, we examined prospectively, in 36 participants, the effect of weight loss on pulse pressure, using the Wilcoxon signed ranked test. Results: At baseline, a 5 kg/m2 increase in BMI was independently associated with a 35%risk relative risk(RR)=1.35, confidence interval(CI)=1.10-1.65, P< 0.01 in the general study population and 19%(RR=1.19, CI=1.07-1.56, P=0.04) in obese normotensives for increasing PP by one quartile after adjustment for other significant variables. After 3 months of diet and exercise intervention, BMI decreased by an average of 10.6%(P< 0.01) and resulted in an 8.8%(P< 0.01) reduction in PP. Conclusions: In the context of obesity, increasing BMI is independently associated with decreasing arterial compliance, as reflected in PP. This association highlights the potential value to cardiovascular health of any reduction in body weight in obese individuals. Objective: Pulse pressure, a marker of arterial vascular properties, has been linked to cardiovascular diseases and complications. This study examined the impact of excess body mass and cardiovascular disease risk factors on pulse pressure (PP). Design: Cross-sectional and prospective study . Methods: Baseline data consist of 219 obese African Americans, with mean ± SD age of 46.8 ± 10.9 years enrolled in a diet and exercise program of weight reduction. A non-invasive monitoring device was used to acquire 24 hourly ambulatory blood pressures. Pulse pressure was calculated as the difference between the average 24-h systolic and diastolic blood pressure and studied as a continuous variable and according to quartiles. The cross-sectional association of pulse pressure with body mass index (BMI) was examined using multivariate linear regression and proportional odds models that controlled for cardiovascular disease risk factors. In addition, we were examining prospectively, in 36 participants, the eff Results: At baseline, a 5 kg / m2 increase in BMI was independently associated with a 35% risk relative risk (RR) = 1.35, confidence interval (CI) = 1.10-1.65, P <0.01 in the general study population and 19% (RR = 1.19, CI = 1.07-1.56, P = 0.04) in obese normotensives for increasing PP by one quartile after adjustment for other significant variables. Diet and exercise intervention, BMI decreased by an average of 10.6% (P <0.01) and resulted in an 8.8% (P <0.01) reduction in PP. Conclusions: In the context of obesity, increasing BMI is independently associated with decreasing arterial compliance , as reflected in PP. This association highlights the potential value to cardiovascular health of any reduction in body weight in obese individuals.