Breast-feeding is encouraged to optimize the health and nutrition of newborn infants. In addition, breast-feeding may impact maternal postpartum weight loss and subsequent body composition. In our study height, weight, waist and hip circumferences were measured in 141 white women between the ages of 25 and 50, from which body mass index (BMI) and waist-to-hip ratios (WHR) were calculated. Percent body fat was assessed using bioelectrical impedance analysis. Food frequency questionnaires were used to evaluate dietary intake. Socioeconomic status, health history, and reproductive history were assessed using a questionnaire. Thirty-one percent of all subjects never attempted breast-feeding, while 39% breast-fed less than one month. A significantly higher proportion of non-breast feeders were overweight (BMI> 27.3kg/m 2 ), had high WHR (>0.8), and excess body fat (>35.6%) (p<0.01). Breast feeders showed significantly higher mean intakes for vitamin A, vitamin C, calcium, iron, thiamin. riboflavin, niacin, folate, vitamin B-6 and zinc (p<0.05); however, the differences were no longer significant when adjusted for calorie intake. Education and income showed significant positive correlations with breast-feeding duration (p<0.01), while breast-feeding duration was negatively correlated with BMI, percent body fat, and WHR (p<0.01). In a combined analysis of covariance, income and education were the strongest predictors of BMI among all subjects, and explained 21% of the variability in BMI values. These results suggest that breast-feeding may be beneficial to a mother's body composition, and that continued efforts to encourage breast-feeding are warranted.