Certification/registration is when an independent and competent third party certifies that a product, service, system, process or material conforms to specific requirements.

For management system certification the most well known examples are the certification of quality management systems and environmental management systems as conforming, respectively, to ISO 9001 and ISO 14001 standards.

In 2007 over 950,000 businesses in 175 countries were certified with quality management systems that comply with ISO 9001, and over 150,000 businesses in 148 countries were certified with environmental management systems that comply with ISO 14001.

ISO, as the publisher of standards, does not issue certificates of conformity to any standard. Certificates of conformity to specified standards are issued by certification/registration bodies, which are independent of ISO and of the businesses they certify. There are over 1100 certification or registration bodies worldwide.

The terms "certification" and "registration" are employed in a broader conformity assessment context than ISO 9001 and ISO 14001 alone and their standardised definitions show that they are not synonymous.

However, in the ISO 9001 and ISO 14001 context, "certification" and "registration" are used interchangeably and they both mean the same thing. One term is preferred over the other depending on the country. Likewise, the bodies that issue ISO 9001 or ISO 14001 certificates are referred to in some countries as "certification bodies" and in others as "registration bodies" or "registrars".

CNAB requires that certification/registration bodies accredited by CNAB accreditation body members comply with ISO/IEC 17021 and/or Guide 65 and the relevant CNAB Guidance or Mandatory Documents. The ISO/IEC Standards/Guides and the CNAB Guidance/Mandatory Documents are designed to ensure that certification/registration bodies are both competent to carry out the work involved and are operated independently of businesses that are certified.

Quality and environmental management system certification assures users and customers that the business has management systems in place that comply with ISO9001 or ISO14001, irrespective of the business and its work. To maintain compliance, standards are monitored by regular surveillance.

Product certification is specific to a particular product produced by a particular business. Product certification assures users and regulators that the certified product complies with the standard(s) specified on the certificate. Product certification may be limited to compliance with one or more standards even though the product may be subject to many standards.