Breastfeeding is considered the best infant feeding method, yet initiation and duration rates in the United States are lower than recommended by medical and public health professionals. Positive attitudes toward breastfeeding of the male partner are important in a mother's success at initiating and maintaining breastfeeding. This study measured the infant feeding attitudes of low-income women and their male partners using the Iowa Infant Feeding Attitude Scale (IIFAS), investigated the reliability and validity of the measure in male partners, and examined the associations of the partner's attitudes with the mother's attitudes and intention to breastfeed. A convenience sample of 112 pregnant women and their male partners completed a survey including sociodemographic items, the IIFAS, and their intended infant feeding method in the hospital and in the first few weeks after the infant's birth (breastfeeding, formula feeding, mixed, and don't know). Mother's and partner's IIFAS scores were highly correlated, and higher scores of both mothers and partners were significantly associated with their intentions to breastfeed. With each increased point on mother's and partner's IIFAS scores, the odds that the mother and her partner intended to breastfeed in the first few weeks increased 12% and 20%, respectively. This is the first U.S. study to validate the IIFAS with male partners. Future research on breastfeeding attitudes and attitude-changing interventions is needed to see if improving partners' attitudes toward breastfeeding will also improve mothers' attitudes and if that increases initiation and duration of breastfeeding.