Despite strong evidence that stable, high-quality child care promotes young children's development, low-income children are less likely to participate in formal and high-quality care than higher-income children and may be more likely to experience multiple, concurrent arrangements due to parents' economic and employment constraints. Child care subsidy programs increase low-income children's access to formal, center-based care, but little is known as to whether subsidies also influence the use of multiple arrangements. This study uses difference-in-difference techniques to estimate the effects of child care subsidy program spending on parents' decisions about the number and type of care arrangements. Results show that state subsidy program spending is associated with a higher likelihood of using a single, center-based arrangement and a lower likelihood of using multiple arrangements. Findings suggest that the unaffordability of child care likely contributes to low-income parents' use of multiple arrangements, and that subsidy programs increase these families' access to center-based care. (author abstract)