Two-Midnight Rule
Medicare policy that generally treats a stay spanning two midnights as appropriate for inpatient admission.
1 min read · Last reviewed May 23, 2026
At a glance
- Category
- Billing
- Primary sources
- 1
- Workspace handoff
- denial workbench →
Where this comes up
This shows up in revenue-cycle work — claim scrubbing, charge entry, posting, A/R follow-up, and month-end close. Billers and practice managers hit this term when reconciling a payment, working a denial queue, or auditing why a claim aged past 60 days.
Full definition
What it is in practice
The CMS Two-Midnight Rule directs that physician orders for inpatient admission are appropriate when the practitioner expects the patient to require hospital care across two midnights. Shorter stays are generally observation/outpatient.
How it shows up in your practice
Document expected length of stay at admission. Misclassification (inpatient vs observation) drives Recovery Audit Contractor recoupments.
Sources
- CMS — Two-Midnight Rule (Inpatient Admission)https://www.cms.gov/medicare/regulations-guidance/two-midnight-rule
Defend Two-Midnight denials in the Denial Workbench
Open denial workbench →Related terms
- BillingInpatient Hospital BillingFacility billing for hospitalized patients, classified using the MS-DRG system under the Acute Inpatient Prospective Payment System.
- BillingMS-DRGMedicare Severity Diagnosis Related Groups — the classification system used to pay inpatient hospital admissions under Medicare's prospective payment system.
- Denials & AppealsRecovery Audit Contractor (RAC)CMS contractors who identify and recover improper Medicare payments through review of paid claims.
D3rx is a healthcare-billing and compliance research aid maintained by D3rx Inc. Articles are drafted by an LLM (Anthropic Claude) against primary HHS, OCR, CMS, eCFR, NIST, and state-regulator publications, and reviewed for restraint and source fidelity by the D3rx team.
Reviewer status: a named credentialed reviewer (CHC, CHPC, or healthcare attorney) is being engaged. Until that engagement is finalized, this page does not claim credentialed review.
Related across the archive
- GlossaryInpatient Hospital BillingFacility billing for hospitalized patients, classified using the MS-DRG system under the Acute Inpatient Prospective Payment System.
- GlossaryMS-DRGMedicare Severity Diagnosis Related Groups — the classification system used to pay inpatient hospital admissions under Medicare's prospective payment system.
- GlossaryRecovery Audit Contractor (RAC)CMS contractors who identify and recover improper Medicare payments through review of paid claims.
- GlossaryObservation CareHospital outpatient status used when the patient requires monitoring but does not meet inpatient admission criteria.
- GlossaryMOON NoticeMedicare Outpatient Observation Notice — required to be issued to patients receiving observation services for more than 24 hours.
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This glossary entry is a research aid for billing and compliance staff. It does not provide legal, medical, or financial advice and does not replace counsel. References cited link to primary sources at HHS, OCR, CMS, eCFR, NIST, and the relevant payer or industry body.