Adverse psychosocial exposures may partially drive the high rates of obesity among blacks. The objective of this study was to prospectively examine the relationship between perceived psychosocial stress and percent change in BMI among adult black men and women. We used data from 756 women and 416 men who were participants in the Pitt County Study, a community-based, prospective cohort study of blacks in eastern North Carolina. Participants were aged 25–50 years of age on entry into the study in 1988 and follow-up was obtained in 2001. Using multivariable linear regression, we calculated the adjusted mean percentage change in BMI over the follow-up period for each tertile of baseline measures of the Perceived Stress Scale (low, medium, and high), adjusted for potential confounders. For black women, higher levels of psychosocial stress at baseline predicted higher adjusted percentage increase in BMI over the 13-year follow-up: low stress 12.0% (95% CI 9.6–14.4), medium stress 16.3% (95% CI 13.7–18.9), and high stress 15.5% (95% CI 13.1–17.8). For black men, perceived stress was not associated with percent BMI change. These data suggest that interventions targeting obesity in black women should consider the potential impact of emotional stress on weight change.