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MOON Form CMS-10611: Outpatient Observation Notice

Hospitals and critical access hospitals give this notice to Medicare patients, including Medicare Advantage enrollees, who receive observation services as outpatients for more than 24 hours. It tells the patient they are an outpatient, not an inpatient, why, and what that means for cost sharing and later skilled nursing facility coverage. The patient signs to show they received and understood it.

Who completes it

Hospital staff fill in the patient name and number; the reason the patient is an outpatient is often written by the treating clinician. The patient or representative signs and dates the notice.

Submitting and payment

How to submit it
Deliver it, with an oral explanation, no later than 36 hours after observation begins, or sooner if the patient is transferred, discharged or admitted. The hospital keeps the signed original in the medical record and gives the patient a paper copy.

Good to know

  • The 24-hour clock starts when observation services are initiated under a physician's order, as documented in the record, using elapsed clock time rather than billed time.
  • It also goes to patients without Part B, patients admitted as inpatients before it was due, and patients for whom Medicare is the primary or secondary payer.
  • In states with their own observation notice laws, hospitals may add state content in the Additional Information section or attach the state notice. The MOON must stay two pages.
  • The 2026 version carries OMB expiration 02/28/2029. CMS posts English and Spanish versions, including large print, with instructions in one download.

Get the official form

Download the current version from the source each time; forms change without notice.

Medicare Outpatient Observation Notice (MOON)

Official page

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How this list is checked

A form is listed only after its name and number were confirmed on the issuing agency’s or insurer’s own website, or in the form itself. Each entry links to that source. The list was last checked in October 2026. Forms and their requirements change without notice, so check the official page for the current version before you complete one.

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Frequently asked questions

When must the MOON be given?

To any Medicare patient receiving more than 24 hours of observation as an outpatient, no later than 36 hours after observation begins. Hospitals may deliver it before 24 hours, which helps meet state laws requiring earlier notice, and must deliver it before 36 hours if the patient is discharged, transferred or admitted.

Is the MOON available in Spanish?

Yes. CMS publishes the MOON in English and Spanish, with large-print versions, in a single download. If the patient cannot read it or understand the oral explanation, the hospital uses interpreters, translators or assistive technology under its usual procedures.

What goes in the reason-for-observation field of the MOON?

The hospital must write why the patient is an outpatient receiving observation rather than an inpatient, along with the patient's name and number. The Additional Information section can carry state-required content, Part A cost sharing if the patient is later admitted, or the inpatient admission date and time.