ImportanceStates resumed Medicaid eligibility redeterminations, which had been paused during the COVID-19 public health emergency, in 2023. This unwinding of the pandemic continuous coverage provision raised concerns about the extent to which beneficiaries would lose Medicaid coverage and how that would affect access to care.ObjectiveTo assess early changes in insurance and access to care during Medicaid unwinding among individuals with low incomes in 4 Southern states.Design, Setting, and ParticipantsThis multimodal survey was conducted in Arkansas, Kentucky, Louisiana, and Texas from September to November 2023, used random-digit dialing and probabilistic address-based sampling, and included US citizens aged 19 to 64 years reporting 2022 incomes at or less than 138% of the federal poverty level.ExposureMedicaid enrollment at any point since March 2020, when continuous coverage began.Main Outcomes and MeasuresSelf-reported disenrollment from Medicaid, insurance at the time of interview, and self-reported access to care. Using multivariate logistic regression, factors associated with Medicaid loss were evaluated. Access and affordability of care among respondents who exited Medicaid vs those who remained enrolled were compared, after multivariate adjustment.ResultsThe sample contained 2210 adults (1282 women [58.0%]; 505 Black non-Hispanic individuals [22.9%], 393 Hispanic individuals [17.8%], and 1133 White non-Hispanic individuals [51.3%]) with 2022 household incomes less than 138% of the federal poverty line. On a survey-weighted basis, 1564 (70.8%) reported that they and/or a dependent child of theirs had Medicaid at some point since March 2020. Among adult respondents who had Medicaid, 179 (12.5%) were no longer enrolled in Medicaid at the time of the survey, with state estimates ranging from 7.0% (n = 19) in Kentucky to 16.2% (n = 82) in Arkansas. Fewer children who had Medicaid lost coverage (42 [5.4%]). Among adult respondents who left Medicaid since 2020 and reported coverage status at time of interview, 47.8% (n = 80) were uninsured, 27.0% (n = 45) had employer-sponsored insurance, and the remainder had other coverage as of fall 2023. Disenrollment was higher among younger adults, employed individuals, and rural residents but lower among non-Hispanic Black respondents (compared with non-Hispanic White respondents) and among those receiving Supplemental Nutrition Assistance Program benefits. Losing Medicaid was significantly associated with delaying care due to cost and worsening affordability of care.Conclusions and RelevanceThe results of this survey study indicated that 6 months into unwinding, 1 in 8 Medicaid beneficiaries reported exiting the program, with wide state variation. Roughly half who lost Medicaid coverage became uninsured. Among those moving to new coverage, many experienced coverage gaps. Adults exiting Medicaid reported more challenges accessing care than respondents who remained enrolled.