BackgroundIn May of 2022, parents living in the United States experienced a dramatic infant formula shortage caused by supply chain issues and the recall of several infant formula products over contamination concerns.MethodsAn anonymous, electronic, cross-sectional survey was designed to understand infant feeding practices, parental experience and perceived support during the crisis.ResultsNinety-nine parents that lived in the U.S. and fulfilled study criteria completed the survey. 66% of respondents were female, and 75% of respondents were recipients of the Special Supplemental Nutrition Program for Women Infant Children (WIC). Parental mean age was 30.0 years, and the mean infant age was 26.8 weeks. The number of individuals that used at least one unsafe infant feeding practice increased from 8% before the infant formula shortage to 48.5% during the shortage (p < 0.001). 79% of parents fed their infants U.S. infant formula brands and 39% of parents fed their infants imported infant formula brands before the shortage which were significantly reduced during the shortage to 27% (p < 0.005) and 11% (p < 0.005), respectively. The percentage of parents that reported infant feeding practices before and during the infant formula shortage significantly increased from 2 to 28% for banked donor milk use (p < 0.005); 5–26% for use of human milk from informal sharing (p < 0.005); and 2–29% for use of watered-down infant formula (p < 0.005). The resources that parents reported as most helpful in navigating the crisis differed by parental sex and WIC recipient status and included other parents, friends, and family; lactation consultants; healthcare providers; and WIC.ConclusionsOur study found that feeding practices in response to the infant formula shortage may pose health risks to infants including nutrition and food insecurity. These data suggest the need for policy changes within regulatory and the healthcare system to provide families with clinical prenatal and postnatal lactation support, access to pasteurized banked donor milk, and access to more commercially available products.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12887-023-04132-9.