Although Hispanic mothers in the United States have slightly higher rates of breastfeeding initiation than the national average, they are more likely to supplement with formula. To describe infant feeding decisions in a sample of 72 urban Hispanic mothers and assess whether demographic and personal factors influence exclusive breastfeeding (EBF) status at 4 months postpartum. The study was longitudinal and included assessments during pregnancy, in the hospital following childbirth, and monthly up to 4 months following birth. Nearly all of the 72 mothers were breastfeeding at discharge after the birth of their infant (94%); half of these were EBF. By 2 months postpartum, the rate of EBF had declined to 26%, dropping to 22% by 4 months. Significant predictors of EBF status at 4 months included the baseline indicator for mother's partner as the most important person in life (adjusted odds ratio [AOR], 5.42; 95% confidence interval [CI], 1.03-28.66) and breastfeeding self-efficacy score at 1 month (AOR, 1.20; 95% CI, 1.07-1.34). These findings have particular relevance in this population, given the high rate of breastfeeding initiation coupled with breastfeeding self-efficacy being a modifiable factor. Support during pregnancy and postpartum, including consultation with a lactation consultant, may increase the self-efficacy of EBF in this low-income population, leading to higher rates of extended EBF among Hispanics.