An audit is a process for documenting and evaluating if a Energy Management System conforms to the ISO 50001 standard.

Internal Audit – is performed within the organization to highlight any non-conformance issues. Once the non-conformances issues are addressed, the organization employs an accredited third party to perform an independent audit.
Third Party Audit – is usually performed after an internal audit is completed by the internal staff of an organization. The Third Party audit is typically performed by an accredited agency or organization.