Complaints register example and template (ISO 9001)

A complaints register is an overview of all the complaints you receive from customers, with the cause, the action and the result for each complaint. The term “complaints register” does not appear in the standard, but it is the evidence that you take complaints seriously. ISO 9001 requires you to collect customer feedback, including complaints (clause 8.2.1). It also requires you to take action when a nonconformity arises from a complaint, and to keep evidence of that action (clause 10.2). Read how to measure customer signals at measuring customer satisfaction. For follow-up, use the CAPA register.

If you want to develop complaint handling further, there is a separate guideline: ISO 10002, published by NEN (Royal Netherlands Standardisation Institute) . It is not mandatory for ISO 9001.

The register is a working document, not an archive. You use it to spot patterns. If the same complaint keeps coming back, there is a cause you have not yet addressed.

Why a register and not a mailbox?

Complaints that only sit in an inbox are not followed up. A register forces you to log every complaint, name an owner and close it. You can also show the register to an auditor or during the management review.

Without a register	With a register
Complaints disappear in the mailbox	Every complaint has a number and an owner
You do not see that the same complaint keeps returning	You count per category and see the pattern
No evidence of follow-up	Actions and closing dates are fixed
Discussion about what happened	Facts are recorded in one line

Template for the complaints register

Use one table with the columns below. Keep it up to date, even if only one complaint comes in per month. If customer names are included, they count as personal data under the Algemene verordening gegevensbescherming (AVG, the Dutch GDPR). Only record what you need, and decide how long you keep it.

Column	What you enter	Example
Number	Ascending, so you can find each complaint	K-2026-014
Date	Date of receipt	12 October 2026
Customer or source	Who complains, and through which channel	Customer, by email
Description	What exactly happened, in one or two sentences	Delivery one day late, no advance notice
Category	Fixed list, for example delivery, quality, communication	Delivery
Severity	Low, medium or high, with a short reason	Medium: customer incurred extra costs
Owner	One person who follows up the complaint	Planner
Cause	What was really going on	Planning not updated after a change by the supplier
Action	What you do to prevent it from happening again	Automatic notification when the delivery date changes
Closing date and result	When it was closed, and whether it works	30 October, no new complaint in November

The “cause” column is the most important. Without a cause, you only fix the symptom. Use root cause analysis for complaints where the cause is not immediately clear.

Example: five lines from a complaints register

A bakery with its own delivery service keeps a register. This is part of the table for one month.

No	Date	Category	Description	Cause	Action	Status
K-014	12 Oct	Delivery	Order one day late	Planning not updated	Automatic notification on change	Closed
K-015	15 Oct	Quality	Bread delivered in damaged packaging	Packaging not checked during packing	Checking step on the packing list	Open
K-016	19 Oct	Communication	Customer not called about the delay	No agreement on calling in case of delay	Procedure amended and shared	Closed
K-017	22 Oct	Delivery	Wrong delivery address	Address not checked when the order was placed	Address check at entry	Open
K-018	26 Oct	Delivery	Order one day late	Same cause as K-014	Notification running, still to be tested	Open

Note line K-018. It has the same cause as K-014, and that is the pattern the register exists to reveal. If the action taken for K-014 had really worked, K-018 should not have happened. Now the owner knows they must check the action.

You only close a complaint once the action has been checked. “Action carried out” is not yet evidence that it works. When you close a complaint, record what you checked and when.

Step by step: setting up a complaints register

Create one place for all complaints

Choose one register, either in a spreadsheet or in your quality software. Agree that every complaint ends up there, including those reported verbally.

Set the categories

Use a fixed list of five to eight categories. Without a fixed list, you cannot count. Only add a category if more than one complaint fits it and the existing categories do not cover it.

Register within one working day

The later you register, the vaguer the description becomes. Record what the customer said, not what you think was happening.

Determine severity and appoint an owner

A complaint involving financial damage or a safety risk is high severity. It gets an owner and a deadline. A small delay is low severity, but it still counts in the pattern.

Find the cause

Ask why it happened until you reach something you can act on. For a serious or recurring complaint, an 8D report helps. For a complaint about product quality, you can also use an Ishikawa diagram.

Review the register monthly

Count per category, look at the number of open complaints and the throughput time. This is the material for your management review and for the internal audit.

What does the auditor want to see in your complaints register?

An auditor does not check whether you have zero complaints. They check whether you follow up complaints and do something about them. They look for:

Complaints recorded consistently, including the small ones.
A cause recorded for every complaint that has been closed.
Recurring complaints that are visible and have a controlled action.
Figures from the register that come back in the management review.
Open complaints that have an owner and a deadline.

Common mistakes

Registering only the big complaints. The pattern often sits in the small ones. Register everything, including the complaint you resolved immediately.

A cause that is “the employee”. That is not a cause. Keep asking what the system allowed to happen.

Closing without checking. A closed complaint that nobody has checked is a sham solution.

A register nobody reads. If the register is not on the agenda of the management review, it disappears. Schedule it in firmly.

No distinction between complaints and advice. A customer who makes a suggestion has not made a complaint. Do record those suggestions, but in a separate category.