To determine whether participation in the Women, Infants, and Children Program is associated with improved maternal and infant health outcomes among homeless women in the Pregnancy Risk Assessment Monitoring System. Analyses were based on Pregnancy Risk Assessment Monitoring System participants from 31 states/cities in the United States, 2000-2007 (n = 272,859). Overall, 4% of women completing the Pregnancy Risk Assessment Monitoring System survey were homeless, with 76% participating in the Women, Infants, and Children Program, a federally-funded supplemental nutrition program for low-income women and children less than 5 years old. Among women in the Pregnancy Risk Assessment Monitoring System survey who reported using the Women, Infants, and Children Program, those experiencing homelessness were older, less educated, less likely to have private health insurance, and more likely to receive government assistance. Homeless women in the Women, Infants, and Children Program compared with those not in the program were significantly more likely to have a higher body mass index, to initiate breastfeeding after delivery, have prenatal care visits, have a longer gestational age, and have a greater infant birth weight. Characteristics of homeless pregnant women choosing to participate in the Women, Infants, and Children Program are consistent with the requirements for program participation for women in general. Homeless women accessing the Women, Infants, and Children Program had better maternal and infant health outcomes. (c) 2010 Elsevier Inc. All rights reserved.