A Maternal Breastfeeding Evaluation Scale was developed from categories identified in qualitative research. Content validity was tested according to procedures described by Imle and Atwood and Lynn. A sample of 442 women who had breastfed completed an instrument of 56 Likert-scale items. A retest questionnaire was completed by a subsample of 28 women. Exploratory factor analysis resulted in three factors, accounting for 38.5 percent of the variance: Maternal Enjoyment/Role Attainment (29 percent), Infant Satisfaction/Growth (5 percent), and Lifestyle/Maternal Body Image (4 percent). A revised 30-item MBFES was developed using items loading strongly on these three factors. Cronbach's alphas for the revised scale and subscales were .93, .93, .88, and .80, respectively. Test-retest correlations (n = 28) were .93, .93, .94, and .82, respectively (p < .001 for all).