Internal Audit Engagement Letter

The internal audit engagement letter states the nature of the audit. It provides notice and scope of the upcoming audit. The auditor provides this to the auditee (could be a client) prior to the audit. The letter prevents surprise reaction from the clients.

This letter can be as simple as an audit agenda or formal as a registration notice.

• the audit team
• the audit team leader
• the audit objectives
• the audit scope and criteria
• the audit time schedule
• the audit dates

Include the above items in the engagement letter.

The audit scope and criteria is determined by the client’s

• policies
• systems
• procedures
• processes
• products
• standards
• laws and regulations
• systems
• specification
• contract requirements

Changes to the scope and criteria should be approved by the auditor and the client.

In ISO 9001 the registration engagement letter will include all the elements of the ISO 9001 standard. In a renewal audit the engagement letter will include only some of the elements.

The internal audit engagement letter can be used when conducting a quality audit.