Feeding infants unscreened, raw human milk from a source other than the mother may pose health risks. The objectives of the Moms2Moms Study were to estimate the proportions of mothers who were aware of breastmilk sharing, considered sharing, and shared milk and to identify associated maternal and child characteristics. All eligible women (n=813) who delivered at The Ohio State University Wexner Medical Center (Columbus, OH) and did not indicate an intention to exclusively "bottle feed" were asked to participate in this cohort by completing a postal questionnaire at 12 months postpartum (499 61% responded). Women who shared milk participated in a follow-up interview. Awareness of milk sharing was high (77%) and positively associated with socioeconomic status, age, non-Hispanic white race, having fed one's infant at the breast, and reporting no difficulty making enough milk. Twenty-five percent considered sharing. Primiparous women (odds ratio OR=2.12; 95% confidence interval CI 1.02, 4.62) and those who delivered preterm (OR=3.27; 95% CI 1.38, 7.30) were more likely to consider feeding milk from another mother. Women with public/no insurance (OR=0.52; 95% CI 0.27, 0.97) were less likely to consider providing milk for someone else; highly educated women were more likely (OR=1.90; 95% CI 1.12, 3.32). Almost 4% of women shared milk and did so among friends or relatives or had a preterm infant who received screened and pasteurized donor milk. Sharing milk among friends and relatives is occurring. Many women are aware of milk sharing and have considered it.