- 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.
- Medcom Systems Inc.
- Medex Northwest
- Media Financial Management Association
- Medical Alliance Partnership
- Medical Association of the State of Alabama
- Medical Business Resources
- Medical Care Access Coalition
- Medical Center - Navicent Health
- Medical Center Barbour
- Medical Center Enterprise
- Medical Center of Central Georgia
- Medical Center of South Arkansas
- Medical Center of Trinity
- Medical City Arlington
- Medical City Fort Worth
- Medical College of Georgia
- Medical College of Georgia, MCG Health System
- Medical deScriptions
- Medical Eye Bank of West Virginia
- Medical Group Management Association
- Medical Mutual