ISO/IEC 17021-1:2015, developed by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) define how certification bodies must operate when auditing and certifying management systems, setting a global baseline for consistent and reliable certification.

ISO/IEC 17021-1:2015 explains what certification bodies must do to deliver trusted results when assessing organizations against standards such as ISO 9001 or ISO 14001. It replaced ISO/IEC 17021:2011, which previously covered these requirements in a single document before the series was expanded into multiple parts. The standard places strong emphasis on independence, requiring certification bodies to avoid conflicts of interest and base decisions on objective evidence. It also requires auditors to be properly qualified and ensures that audits follow consistent, structured steps from planning through to final certification decisions.

In practice, ISO/IEC 17021-1 requires certification bodies to:

• Keep certification decisions separate from commercial or other influences
• Use auditors with the right skills, knowledge, and sector experience
• Apply clear and repeatable audit methods across all clients
• Provide transparent information about their processes and decisions
• Take full responsibility for granting, maintaining, suspending, or withdrawing certification

The standard also explains how audits are planned and carried out, how audit teams are selected, and how certification decisions are reviewed and maintained over time. It requires ongoing monitoring of certified organizations through surveillance audits to ensure continued compliance, reinforcing that certification is a continuous process rather than a one-time check.

ISO/IEC 17021-1 is the core part of the ISO/IEC 17021 series. While Part 1 sets the general requirements for all certification bodies, the other parts of the series provide additional rules, mainly focused on auditor competence for specific management system disciplines. For example, separate parts define competence requirements for auditing quality management, environmental management, occupational health and safety, and other specialized areas. These additional parts build on Part 1 and ensure that auditors have the right expertise for the systems they assess.

By aligning how certification bodies operate across countries, ISO/IEC 17021-1 supports confidence in management system certification and helps ensure that certificates issued in one country are recognized and trusted in others. ISO/IEC 17021-1 plays a central role in the global quality infrastructure by ensuring certification bodies operate with integrity, consistency, and technical competence.

Further details are available in ISO/IEC 17021-1 from ISO.