Objective: In 2009, the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) implemented new food packages to improve dietary intake among WIC participants. This paper examines how the healthfulness of food purchases among low-income households changed following this reform.Methods: Point-of-sale data for 2137 WIC-participating and 1303 comparison households were obtained from a regional supermarket chain. The healthfulness of purchased foods and beverages was determined per their saturated fat, sugar, and sodium content. A pre-post assessment (2009-2010) of the product basket healthfulness was completed using generalized estimating equation models. Data were analyzed in 2015.Results: At baseline, healthy products accounted for most of the food volume purchased by WIC participants, but beverages were dominated by moderation (less healthy) items. With new subsidies for fruit, vegetables and whole grains, the WIC revisions increased the volume of healthy food purchases of WIC-participating households by 3.9% and reduced moderation foods by 1.8%. The biggest improvements were reductions in moderation beverages (down by 24.7% in volume), driven by milk fat restrictions in the WIC food package revisions. The healthfulness of the product basket increased post-WIC revisions; mainly due to a reduction in the volume of moderation food and beverages purchased (down by 15.5%) rather than growth in healthy products (up by 1.9%). No similar improvements were seen in a comparison group of low-income nonparticipants.Conclusions: After the WIC revisions, the healthfulness of participant purchases improved, particularly for beverages. Efforts to encourage healthy eating by people receiving federal food assistance are paying off. [ABSTRACT FROM AUTHOR]