| Marshall County Hospital | Benton, KY | Critical Access Hospitals | 2 stars |
| Marshall Medical Center | Lewisburg, TN | Critical Access Hospitals | Not rated |
| Marshall Medical Centers | Boaz, AL | Acute Care Hospitals | 3 stars |
| Marshfield Medical Center - Ladysmith | Ladysmith, WI | Critical Access Hospitals | Not rated |
| Martin County Hospital District | Stanton, TX | Critical Access Hospitals | Not rated |
| Mason District Hospital | Havana, IL | Critical Access Hospitals | Not rated |
| Mason General Hospital & Family of Clinics | Shelton, WA | Critical Access Hospitals | 2 stars |
| Massac Memorial Hospital | Metropolis, IL | Critical Access Hospitals | 2 stars |
| Matagorda Regional Medical Center | Bay City, TX | Acute Care Hospitals | 5 stars |
| Mayers Memorial Hospital | Fall River Mills, CA | Critical Access Hospitals | Not rated |
| Mc Camey Hospital | McCamey, TX | Critical Access Hospitals | Not rated |
| Mc Donough District Hospital | Macomb, IL | Acute Care Hospitals | 3 stars |
| McAlester Regional Health Center | McAlester, OK | Acute Care Hospitals | 3 stars |
| Meade District Hospital | Meade, KS | Critical Access Hospitals | Not rated |
| Medical Arts Hospital | Lamesa, TX | Acute Care Hospitals | Not rated |
| Medical Center Barbour | Eufaula, AL | Critical Access Hospitals | Not rated |
| Medical Center Hospital | Odessa, TX | Acute Care Hospitals | 3 stars |
| Medical College of Virginia Hospitals | Richmond, VA | Acute Care Hospitals | 4 stars |
| Medical West, an Affiliate of UAB Health System | Bessemer, AL | Acute Care Hospitals | 3 stars |
| Medicine Lodge Memorial Hospital | Medicine Lodge, KS | Critical Access Hospitals | Not rated |
| Medina Regional Hospital | Hondo, TX | Critical Access Hospitals | Not rated |
| Melissa Memorial Hospital | Holyoke, CO | Critical Access Hospitals | Not rated |
| Memorial Health | Lawton, OK | Acute Care Hospitals | 2 stars |
| Memorial Hospital | Chester, IL | Critical Access Hospitals | Not rated |
| Memorial Hospital | Abilene, KS | Critical Access Hospitals | 2 stars |
| Memorial Hospital | Gonzales, TX | Acute Care Hospitals | Not rated |
| Memorial Hospital | Seminole, TX | Critical Access Hospitals | Not rated |
| Memorial Hospital | Dumas, TX | Critical Access Hospitals | Not rated |
| Memorial Hospital and Manor | Bainbridge, GA | Acute Care Hospitals | 1 star |
| Memorial Hospital Miramar | Miramar, FL | Acute Care Hospitals | 5 stars |
| Memorial Hospital of Texas County Authority | Guymon, OK | Critical Access Hospitals | Not rated |
| Memorial Hospital Pembroke | Pembroke Pines, FL | Acute Care Hospitals | 4 stars |
| Memorial Hospital Sweetwater County | Rock Springs, WY | Critical Access Hospitals | Not rated |
| Memorial Hospital West | Pembroke Pines, FL | Acute Care Hospitals | 3 stars |
| Memorial Regional Hospital | Hollywood, FL | Acute Care Hospitals | 3 stars |
| Mercer County Joint Township Community Hospital | Coldwater, OH | Acute Care Hospitals | 3 stars |
| Mercy Medical Center | Roseburg, OR | Acute Care Hospitals | 4 stars |
| Metro Nashville General Hospital | Nashville, TN | Acute Care Hospitals | 4 stars |
| Mid Valley Hospital & Clinic | Omak, WA | Critical Access Hospitals | Not rated |
| Middle Park Medical Center | Kremmling, CO | Critical Access Hospitals | Not rated |
| Midland Memorial Hospital | Midland, TX | Acute Care Hospitals | 1 star |
| Miller County Hospital | Colquitt, GA | Critical Access Hospitals | Not rated |
| Mineral Community Hospital | Superior, MT | Critical Access Hospitals | Not rated |
| Minneola District Hospital | Minneola, KS | Critical Access Hospitals | Not rated |
| Missouri River Medical Center | Fort Benton, MT | Critical Access Hospitals | Not rated |
| Mitchell County Hospital District | Colorado City, TX | Critical Access Hospitals | Not rated |
| Modoc Medical Center | Alturas, CA | Critical Access Hospitals | 4 stars |
| Monroe County Hospital | Forsyth, GA | Critical Access Hospitals | Not rated |
| Morehouse General Hospital | Bastrop, LA | Acute Care Hospitals | 2 stars |
| Morgan Medical Center | Madison, GA | Critical Access Hospitals | Not rated |