Despite the increase in obesity among women of reproductive ages, few studies have considered maternal obesity as a risk factor for breast-feeding success. We tested the hypothesis that women who are obese (BMI = 30–34.9) and very obese (BMI ≥35) before pregnancy are less likely to initiate and maintain breast-feeding than are their normal-weight counterparts (BMI = 18.5–24.9) among white and black women. Data from 2000 to 2005 South Carolina Pregnancy Risk Assessment Monitoring System (PRAMS) were used. The overall response rate was 71.0%; there were 3,517 white and 2,846 black respondents. Black women were less likely to initiate breast-feeding and breast-fed their babies for a shorter duration than white women. Compared to normal-weight white women, very obese white women were less likely to initiate breast-feeding (odds ratio: 0.63; 95% confidence interval (CI) = 0.42, 0.94) and more likely to discontinue breast-feeding within the first 6 months (hazard ratio (HR) = 1.89; 95% CI: 1.39, 2.58). Among black women, prepregnancy BMI was neither associated with breast-feeding initiation nor with breast-feeding continuation within the first 6 months. Because very obese white women are less likely to initiate or continue breast-feeding than other white women, health professionals should be aware that very obese white women need additional breast-feeding support. Lower rates of breast-feeding among black women suggest that they should continue to be the focus of the programs and policies aimed at breast-feeding promotion in the United States.