- McGuire Memorial
- McGuire Woods LLP
- McHenry County College
- MCHS - Franciscan Healthcare - La Crosse
- MCHS Franciscan Healthcare
- McKay-Dee Hospital
- McKee Medical Center
- McKenzie County
- McKesson Bio Services
- McKessonHBOC
- McKinley County
- McKinley Marketing Inc.
- McKinney and Company
- McKnight's Long-Term Care News
- McLane Southeast
- McLaren Flint
- McLaren Greater Lansing
- McLaren Macomb
- McLean Cargo Specialists, Inc.
- McLean County Board
- McLennan County Medical Education and Research Foundation
- McNamara and Carver, P.A.
- McNeil CS and P
- McNeil Technologies
- MD Anderson Cancer Center Orlando
- MDI Technologies
- MDS Pharma Services
- MDS Research Company, Inc.
- Meade Energy Corp.
- Meadowbrook Internists, P.C.
- Meadows at Salem Run
- Meadowview Regional Medical Center
- Meadville Medical Center
- Meals on Wheels Asheville-Buncombe County
- Meals on Wheels Association of America
- Mease Countryside Hospital
- Mease Dunedin Hospital
- Mechanical Contractors Association of America
- MECI PA Racing Services, Inc.
- Mecklenburg County Government
- Mecklenburg County Health Department
- Mecklenburg County Medical Society
- Mecosta-Osceola United Way
- MecyFirst
- Med Center Health Medical Center EMS
- Med Flight of Ohio
- Med Health Center
- Med Nova USA-Inc.
- MED TEK Resources, Inc.
- Med-Loz Lease Service, Inc.