- Marble Rock Fire/Rescue
- Marcos de Niza HOSA
- Marcum and Wallace Memorial Hospital
- Margaret J. Weston Medical Center
- Margaretville Memorial Hospital
- Maria Parham Medical Center
- Marian Manor
- Marian Regional Medical Center
- Marian University
- Maricopa County
- Maricopa County Department of Public Health
- Maricopa Integrated Health System
- Maricopa Medical Center
- Marietta College
- Marietta Memorial Hospital
- Marimon Business Systems, Inc.
- Marina Del Ray Hospital
- Marina Suites - Dewey Beach
- Marine Corps Material Comm.LHP
- Marine Credit Union
- Marine Spill Response Corporation
- Mariners Hospital
- Marines Caldwell County
- Marion County Medical Center
- Marion Drury Inn
- Marion General Hospital
- Marion General Hospital
- Marion School District
- Mark III Systems Inc.
- Mark Kamin and Associates, Inc - Houston, TX
- Mark Kamin and Associates, Inc - Palo Alto
- Mark Sofman
- Mark Twain Medical Center
- Mark W. Dixion, CMT, BCTMB
- Markel Corporation
- Marken
- Marker International
- Marketing Ally
- Marketing Business Services and Event Planners
- Marketing General Inc
- Marketing Group, Inc.
- Marketvision Research
- Markmaster, Inc.
- Marquesa Hotel
- Marquette County
- Marriott Cincinnati Airport
- Marriott Cincinnati North
- Marriott Cincinnati Northeast
- Marriott Guest Services
- Marriott Houston West Loop by the Galleria