ImportanceAdvance Child Tax Credit (CTC) monthly payments administered to more than 35 million households with children in the US between July and December 2021 were associated with a substantial decrease in food insufficiency. These monthly payments expired in January 2022 after Congress failed to extend the policy, and the subsequent impact on food insufficiency is currently unknown.ObjectiveTo assess whether the expiration of monthly CTC payments in January 2022 was associated with changes in food insufficiency in US households with children.Design, Setting, and ParticipantsThis study used repeated cross-sectional, nationally representative data from multiple waves of the Household Pulse Survey, conducted by the US Census Bureau. Online data collection occurred from July 21, 2021, to July 11, 2022, and data analysis was performed in July 2022.ExposuresThe first missed advance CTC payment on January 15, 2022.Main Outcomes and MeasuresThe main outcome was unadjusted prevalence of household food insufficiency. Event study specification was used to estimate the association between the expiration of the CTC payments and household food insufficiency with the exposure of being in a household with children present.ResultsThe sample (592 044 respondents, representing households with and without children, for a weighted population size of 123 350 770 individuals) was majority female (362 286 individuals [51.3%]) and non-Hispanic White (425 497 individuals [62.2%]), and a plurality of respondents (248 828 [48.3%]) were aged 25 to 44 years at the time of the survey. During the survey wave just before CTC expiration (reference wave, December 29, 2021, to January 10, 2022), unadjusted household food insufficiency was 12.7% among households with children. In late January and early February 2022, following the first missed CTC monthly payment, 13.6% of households with children reported food insufficiency, increasing to 16.0% by late June and early July 2022. The event study specification estimated a 3.2 percentage point increase (95% CI, 1.4-5.0 percentage points; P < .001) in food insufficiency by the most recent wave available after the first missed CTC payment (June 29 to July 11, 2022) among households with children compared with the reference wave, a 25% increase.Conclusions and RelevanceThe findings of this study suggest that there was an increase in food insufficiency among households with children after they stopped receiving monthly CTC payments. Given the well-documented associations between inability to afford food and poor health outcomes across the life span, Congress should consider swift action to reinstate this policy.