- National Conference Center
- National Conference of Community Justice
- National Conference on Public Employee Retirement Systems
- National Congress for Community Economic Development
- National Congress of American Indians
- National Cooperative Bank
- National Corn Growers Association
- National Council of Churches
- National Council of Gray Panthers Networks
- National Council of Higher Education Loan Programs, Inc.
- National Council of Teachers of Mathematics
- National Council on the Aging, Inc.
- National Court Reporters Association
- National Cremation Society
- National Crime Prevention Council
- National Datacare Corporation
- National Defense Industrial Association
- National Defense Transportation Association
- National Demolition Association
- National Dental Association
- National Dental EDI Council
- National Directory of Certified Public Accountants
- National Disease Research Interchange
- National Education Association
- National Electric Manufacturers Association
- National Electrical Contractors Association
- National Electrical Manufacturers Association
- National Exchange Bank and Trust
- National Federation of Asian American United Methodists
- National Federation of Independent Business
- National Federation of Independent Business, Marketing Department NFIB)
- National Fire Protection Association
- National Fluid Power Association
- National Football League Players Association Atlanta
- National Fuel Gas Co.
- National Ground Water Association
- National Guard Bureau - Counterdrug Programs
- National Health Care For the Homeless Council
- National Highway Traffic Safety Agency
- National Hispanic Council on Aging
- National Housing Endowment
- National Indian Council on Aging, Inc.
- National Institute of Corrections
- Institutos Nacionales de la Salud
- National Insurance Association
- National Jewish Health
- National Juneteenth Observation Foundation
- National Kidney Foundation
- National Kidney Foundation of Arizona
- National Kidney Foundation of East TN