- Mt Grant General Hospital
- Mt San Rafael Hospital
- Mt Sinai Hospital Medical Center
- Mt Washington Pediatric Hospital
- Muenster Memorial Hospital
- Muleshoe Area Medical Center
- MultiCare Allenmore Hospital
- MultiCare Auburn Medical Center
- MultiCare Capital Medical Center
- MultiCare Covington Medical Center
- MultiCare Deaconess Hospital
- MultiCare Good Samaritan Hospital
- MultiCare Tacoma General Hospital
- MultiCare Valley Hospital
- MultiCare Yakima Memorial
- Multy Medical Facilities Corporation
- Munising Memorial Hospital
- Munson Healthcare Cadillac Hospital
- Munson Healthcare Charlevoix Hospital
- Munson Healthcare Grayling Hospital
- Munson Healthcare Manistee Hospital
- Munson Healthcare Otsego Memorial Hospital
- Munson Healthcare Paul Oliver Memorial Hospital
- Munson Medical Center
- Murray Calloway County Hospital
- Murray County Medical Center
- MUSC Health Black River Medical Center
- MUSC Health Chester Medical Center
- MUSC Health Columbia Medical Center Downtown
- MUSC Health Columbia Medical Center Northeast