Fact check: What are the estimated costs of providing Medicaid to undocumented immigrants in the US?

Executive Summary — A Narrow but Conflicted Picture of Costs

The available studies show no single national estimate for the cost of enrolling undocumented immigrants in Medicaid; instead, analysts rely on state-level models and a patchwork of assumptions about eligibility, take-up, and health spending. Recent state-focused analyses for Connecticut provide the most concrete numbers, with estimated state costs ranging roughly from $38 million up to $252 million depending on scenarios and timeframes ^{[1] [2]}. Broader national figures remain elusive because of variation in state policies, existing emergency-only coverage, and evidence that unauthorized immigrants currently use less health care per person than US-born residents ^{[3] [4] [5]}.

1. Why Connecticut dominates the conversation — local numbers, national implications

Researchers have produced the clearest numeric estimates by modeling Medicaid expansions in Connecticut, and these studies supply a range of cost scenarios rather than a single figure: one RAND analysis estimated $83–$121 million under certain expansion designs, while a later modeling exercise broadened scenarios to about $38.6–$252.4 million depending on eligibility groups and behavioral assumptions ^{[2] [1]}. These figures are state-budget focused and reflect Connecticut’s population, baseline uninsured rates, and policy choices; they cannot be extrapolated linearly to other states because per-capita costs and undocumented population shares vary substantially across states ^{[2] [3]}.

2. What drives variation in cost estimates — take-up, utilization, and baseline coverage

Cost estimates depend primarily on three modeling levers: assumed enrollment (take-up) rates, projected changes in utilization when people gain full coverage, and whether existing emergency or state-funded programs already offset needs. Studies present multiple scenarios because modest differences in assumed health care use or participation rates produce large swings in projected state costs, explaining why the same researchers present several outcomes from conservative to expansive ^{[1] [2]}. Analyses further note that many states already provide emergency Medicaid and some state-funded full-coverage programs, which change marginal costs of additional eligibility ^{[3] [6]}.

3. Evidence that undocumented immigrants currently use less care — why it matters

Cross-study evidence indicates unauthorized immigrants have lower per-capita health spending and less ED use compared with US-born residents, which influences forward-looking cost models. A multi-year analysis found unauthorized immigrant health spending accounted for about $15.4 billion annually overall and presented much lower per-person emergency department spending than natives, a pattern that modelers use to justify lower per-enrollee cost assumptions in expansion scenarios ^{[4] [5]}. If new enrollees only partially increase utilization because of cultural, linguistic, or access barriers, net state costs could be lower than headline estimates that assume full utilization convergence with citizens ^{[4] [2]}.

4. The missing national estimate — data gaps and policy heterogeneity

No recent study in the reviewed set offers a comprehensive national Medicaid-cost estimate for undocumented immigrants; authors explicitly caution that state policy variation and data limits prevent simple aggregation. National extrapolation is undermined by 37 states’ reliance on emergency Medicaid versus 12 states running state-sponsored full or near-full coverage programs, leaving large coverage gaps and divergent fiscal baselines ^{[3] [6]}. Researchers emphasize that better administrative data on undocumented populations, standardized take-up measures, and cross-state modeling would be necessary before producing a defensible nationwide cost figure ^{[3] [7]}.

5. Alternative viewpoints and potential agendas in the literature

State-focused cost estimates can be framed to support different policy outcomes: advocates for expansion highlight increased coverage and potential long‑run savings from preventive care, while fiscal conservatives emphasize upfront state-budget impacts under high take-up scenarios. The Connecticut studies present multiple scenarios to allow policymakers to weigh tradeoffs, but readers should note that projections reflect assumptions about behavior and spending patterns that can be chosen to produce larger or smaller cost estimates ^{[2] [1]}. Narrative reviews stress methodological barriers and call for cautious interpretation rather than definitive fiscal claims ^{[7] [3]}.

6. Bottom line for policymakers and journalists seeking a simple answer

There is no authoritative national price tag in the reviewed literature; the best empirical anchors are state models like Connecticut’s showing tens to a few hundred million dollars in state costs depending on choices about eligibility and assumptions ^{[1] [2]}. Any national estimate would require explicit assumptions about undocumented population shares, per‑capita utilization convergence with citizens, federal versus state financing roles, and the effect of existing emergency and state-funded programs—none of which are uniform across the country ^{[3] [6]}.