- McHenry County College
- McKnight's Long-Term Care News
- McLean County Board
- Medcom Systems Inc.
- Media Financial Management Association
- Memorial Health System
- Memorial Medical Center
- Methodist College
- Metropolitan Chicago Healthcare Council
- Metropolitan Family Services
- MetroSouth Medical Center
- Midwestern University
- Miller Group Media
- Millikin University
- Million Dollar Round Table
- Mitsubishi Motors North America, Manufacturing Division
- Morris Hospital
- Morrison Institute of Technology
- Motorola
- Mount Sinai
- Mount Zion United Methodist Church
- National Association of Realtors
- National Kidney Foundation of Illinois, Inc.
- National Louis University
- National Professional Group
- National Roofing Contractors Association
- National Runaway Switchboard
- NCCHC
- New Market Visions
- North American Retail Dealers Association
- North Shore Legacy Health System
- Northeastern Illinois University
- Northern Illinois University
- Northern Illinois University, School of Nursing
- Northrop Grumman
- NorthShore Swedish Hospital
- Northwest Community Healthcare
- Northwestern Community Hospital
- Northwestern Huntley Hospital
- Northwestern Lake Forest Hospital
- Northwestern Lake Forrest Hospital
- Northwestern McHenry Hospital
- Northwestern Medicine Palos
- Northwestern Memorial Hospital
- Northwestern Memorial Hospital Organ Transplantation Program
- Northwestern University
- Oak Forest Health Center - Cook County Health and Hospitals System
- Orbitz
- Organ Recovery Systems
- Orthopaedic Research Society