ACA Q&AMay 15, 2026·5 min read·By Jacob Posner, Founder & Editor
Does ACA Marketplace Insurance Cover Preexisting Conditions? (2026)
Short answer: Yes. All ACA marketplace plans must cover preexisting conditions.
Full answer: Yes. All ACA marketplace plans must cover preexisting conditions under 42 U.S.C. § 300gg-3 (Section 1201 of the Patient Protection and Affordable Care Act, Pub. L. 111-148). Since January 1, 2014, marketplace insurers cannot deny coverage, charge higher premiums, or impose exclusions based on a health condition that existed before enrollment. Important exception: short-term limited-duration (STLD) plans are NOT ACA-compliant and CAN deny coverage for preexisting conditions.
One of the most consequential rules in American health insurance law: ACA marketplace plans cannot turn you down, charge you more, or exclude treatment for a health condition you had before you enrolled. This protection applies whether your condition is cancer, diabetes, asthma, heart disease, a prior surgery, or anything else in your medical history.
This guide explains exactly what the law requires, which plan types are covered by the rule, and the one major loophole you need to know: short-term limited-duration plans are NOT subject to this protection. If you're evaluating whether to enroll, see can I buy ACA outside open enrollment and does the ACA cover mental health.
Coverage Breakdown
Coverage by type
Plan Type
Preexisting Conditions Covered
Notes
ACA Marketplace Plan (individual or family)
Yes
Full prohibition on preexisting exclusions since Jan 1, 2014 (42 U.S.C. 300gg-3)
ACA Employer-Sponsored Plan (small or large group)
Yes
Same prohibition applies to group market plans. Grandfathered plans have limited carve-outs.
Short-Term Limited-Duration (STLD) Plan
No
Not ACA-compliant. Can deny coverage or exclude benefits for preexisting conditions.
Association Health Plan (non-ACA-compliant)
Varies
Depends on state regulation. Some can exclude preexisting conditions if not ACA-compliant.
Medicaid (ACA expansion or traditional)
Yes
Medicaid has never allowed preexisting condition exclusions. Available in 40 states plus DC under ACA expansion.
Grandfathered plans (enrolled before March 23, 2010 and unchanged since) are largely exempt from this rule but are rare in 2026. STLD plans are capped at 4 months total duration under 2024 federal rules.
What the Law Actually Says: The Preexisting Condition Prohibition
Section 1201 of the Patient Protection and Affordable Care Act (Pub. L. 111-148, signed March 23, 2010) added Section 2704 to the Public Health Service Act, now codified at 42 U.S.C. 300gg-3. It reads: 'A group health plan and a health insurance issuer offering group or individual health insurance coverage may not impose any preexisting condition exclusion with respect to such plan or coverage.' This rule took full effect January 1, 2014.
The prohibition has three components insurers cannot do: (1) deny enrollment based on a preexisting condition, (2) charge higher premiums because of health status or medical history, and (3) impose waiting periods or benefit exclusions for a preexisting condition. Before this law, an insurer could legally refuse to cover your cancer treatment because you had cancer before you enrolled.
Cancer (any type, any stage)
Diabetes (Type 1 or Type 2)
Heart disease, hypertension
Asthma, COPD, other respiratory conditions
Mental health diagnoses (depression, bipolar, anxiety)
HIV/AIDS, hepatitis
Pregnancy (insurers cannot treat a prior pregnancy as a preexisting condition)
Genetic information, cannot be treated as a preexisting condition absent an actual diagnosis
The 10 Essential Health Benefits: What ACA Plans Must Cover
Beyond banning preexisting condition exclusions, ACA marketplace plans must cover the 10 Essential Health Benefits (EHBs). This matters for people with preexisting conditions because insurers cannot design a plan that technically covers you but excludes the specific treatments your condition requires. Mental health parity rules also apply — see does the ACA cover mental health.
Ambulatory patient services (outpatient care)
Emergency services
Hospitalization
Maternity and newborn care
Mental health and substance use disorder services
Prescription drugs
Rehabilitative and habilitative services and devices
Laboratory services
Preventive and wellness services and chronic disease management
Pediatric services, including oral and vision care
The Major Loophole: Short-Term Plans Are NOT Protected
Short-term limited-duration (STLD) plans are explicitly excluded from the definition of 'individual health insurance coverage' under the Public Health Service Act. That means STLD plans are not required to cover preexisting conditions, not required to cover the 10 essential health benefits, and can deny your claim after the fact by investigating whether a condition predated your enrollment.
Federal rules finalized in 2024 cap STLD plans at 4 months total duration including renewals. But even at 4 months, these plans can leave you with an uncovered claim in the middle of cancer treatment if the insurer determines the cancer is a preexisting condition. If you have a chronic illness, significant medical history, or are currently in treatment, avoid STLD plans entirely.
You may qualify for free health insurance.
Our 2-minute screener checks Medicaid, ACA, Medicare, CHIP, and more. Most uninsured Americans qualify for $0/month coverage they didn't know about.
The preexisting condition protections are permanent and unchanged for 2026. However, 2026 brings a significant affordability change: the enhanced premium tax credits from the American Rescue Plan Act (ARPA) and the Inflation Reduction Act (IRA) expired December 31, 2025. The subsidy cliff is back. Households earning more than 400% of the 2025 federal poverty level ($128,600 for a family of four) no longer qualify for marketplace subsidies in 2026, regardless of what percentage of their income the premium represents.
If your income is above that threshold and you have preexisting conditions, you still have full ACA protections, but you will pay full unsubsidized premiums. Check the ACA screener to confirm your 2026 subsidy eligibility before assuming your costs have not changed.
If You Cannot Afford a Marketplace Plan: Other Options
The preexisting condition protections are strongest in ACA marketplace plans, but cost may still be a barrier in 2026. Three main alternatives exist for people who cannot afford marketplace premiums.
Coverage alternatives for people with preexisting conditions who cannot afford marketplace plans
Option
Preexisting Conditions Covered
Who Qualifies
Medicaid (ACA expansion)
Yes, fully
Income up to 138% FPL in 40 states plus DC
CHIP
Yes, fully
Children under 19 in households below state income limits
ACA marketplace with subsidy
Yes, fully
Income 100% to 400% FPL in 2026 (subsidy cliff restored)
The 10 non-expansion states are AL, FL, GA, KS, MS, SC, TN, TX, WI, and WY. Residents there may have a coverage gap if income is below 100% FPL and they do not qualify for traditional Medicaid.
Source: healthcare.gov, Medicaid.gov, KFF 2026
Frequently Asked Questions
Can an ACA marketplace plan deny me coverage because of a preexisting condition?
No. Under 42 U.S.C. 300gg-3, ACA marketplace plans cannot deny enrollment, charge higher premiums, or exclude treatment for any condition that existed before your coverage began. This rule has applied to all individual and small-group marketplace plans since January 1, 2014.
What counts as a preexisting condition under the ACA?
Any health condition you had before your coverage start date is a preexisting condition. Examples include cancer, diabetes, heart disease, asthma, mental health diagnoses, HIV, hepatitis, prior pregnancies, and past surgeries. Even a condition you were not diagnosed with but had symptoms of can qualify. Genetic information alone (without a diagnosis) cannot be treated as a preexisting condition.
Do short-term health plans cover preexisting conditions?
No. Short-term limited-duration (STLD) plans are not ACA-compliant and are legally allowed to deny coverage, exclude benefits, or rescind claims for preexisting conditions. Federal rules cap STLD plans at 4 months total in 2026. If you have chronic conditions or ongoing treatment, avoid these plans entirely and use an ACA marketplace plan instead.
Can an insurance company charge me more because I am sick?
No, on ACA marketplace plans. Insurers selling marketplace plans can only vary premiums based on age (up to a 3-to-1 ratio), geographic area, tobacco use (up to 1.5-to-1), and whether a plan covers individuals or a family. Health status and medical history cannot affect your premium on ACA-compliant plans.
I missed open enrollment. Can I still enroll if I have a preexisting condition?
You can enroll during a Special Enrollment Period (SEP) if you have a qualifying life event: losing other coverage, getting married, having a baby, moving to a new coverage area, gaining citizenship, and several others. Outside a SEP or open enrollment, you cannot enroll in a marketplace plan regardless of your medical history. Medicaid is open year-round with no enrollment windows.
Are preexisting condition protections at risk of being eliminated?
As of 2026, 42 U.S.C. 300gg-3 remains fully in effect. Prior legal challenges (including Texas v. United States) did not overturn this provision. Congress has not passed legislation repealing it. However, legislative or judicial changes are always possible. The most current status is on healthcare.gov.
Does Medicaid also cover preexisting conditions?
Yes. Medicaid has never allowed preexisting condition exclusions. Medicaid covers all medically necessary services for enrolled members regardless of any conditions they had before enrollment. As of 2026, 40 states plus DC have expanded Medicaid to cover adults earning up to 138% of the federal poverty level (about $22,025 for an individual).
How does the 2026 subsidy cliff affect people with preexisting conditions?
The preexisting condition protections are unchanged in 2026. But the enhanced premium tax credits from ARPA and the IRA expired December 31, 2025. Households earning more than 400% of the 2025 FPL no longer qualify for marketplace subsidies in 2026. This means some people with preexisting conditions who relied on enhanced subsidies now face significantly higher unsubsidized premiums. Use the ACA screener to check your 2026 subsidy status.
You may qualify for free health insurance.
Our 2-minute screener checks Medicaid, ACA, Medicare, CHIP, and more. Most uninsured Americans qualify for $0/month coverage they didn't know about.
3. KFF: The Affordable Care Act 101 — KFF policy overview of the ACA's core consumer protections including the preexisting condition prohibition and essential health benefits requirement.
