Objective. To identify racial/ethnic differences in prevalence and the factors that influence decisions to breastfeed among adolescent mothers. Methods. A total of 696 Mexican-American, African-American, and Caucasian adolescent mothers #18 years of age were interviewed on the postpartum ward of university hospital within 48 hours of delivery. Self-reported factors associated with the decision to breastfeed were assessed. Results. The decision to breastfeed was reported by 55% of Mexican-American, 45% of Caucasian, and 15% of African-American adolescent mothers. With the exception of perceived benefits of breastfeeding and exposure to educational materials, most factors associated with breastfeeding differed by race/ethnicity. Among Mexican-Americans, important factors included having relied on feeding advice (adjusted odds ratio [AOR]= 7.6); the feeding preference of a partner (AOR = 7.0) or mother (AOR = 6.6); and feeding decisions made in early pregnancy (AOR = 4.7). Among African-Americans, important factors included living with a partner (AOR= 10.6); having a mother who breastfed (AOR= 5.9); the feeding preference of a partner (AOR = 5.6) or health care provider (AOR = 4.7); and low family support (AOR 3.4). Among Caucasians, health care providers' feeding preference (AOR = 6.1) having two or more breastfeeding role models (AOR = 4.1); not being enrolled in Women, Infants, and Children's Supplemental Nutrition Program (AOR = 3.0) having relied on infant-feeding advice (AOR = 3.0); and prenatal alcohol use (AOR= 2.6) were associated with the decision to breastfeed. Conclusions. Prevalence and influences to breastfeed differ by patient race/ethnicity. We speculate that targeting the adolescent mother and members of her support system, educating them before and during pregnancy, and stressing benefits of this method while eliminating misinformation, especially among African-Americans, may be important intervention strategies to promote breastfeeding.