CMS Contact Number

0800 171 2345

The Child Maintenance Service is used to arrange payments towards a child’s living costs if an agreement cannot be reached privately. You can contact the Child Maintenance Service on the number above.

CMS Opening Hours

Department Opening Hours
General Enquiries Monday to Friday:
8 am to 6 pm
Individuals Monday to Friday:
8 am to 6 pm
Employer Helpline Monday to Friday:
8 am to 6 pm
Self-Service Helpline Monday to Friday:
8 am to 6 pm
Changes in Circumstance Monday to Friday:
8 am to 6 pm

Child Maintenance Service

Child Maintenance is used as financial support for a child’s living costs after the parents have separated. You can arrange this yourself privately, but if you can’t reach an agreement, you must contact the Child Maintenance Service, who intervene if an arrangement can’t be made. They can arrange for payments to be taken from one parent and passed to the other payments. They also have the ability to take action if a payment hasn’t been made. If you have a question which relates to the CMS, call the CMS contact number. When you call this number, you will reach Child Maintenance Options, which is the overall organisation for setting up child maintenance. From here, you can ask to speak to the Child Maintenance Service if you have an existing claim, or you can speak to them for impartial advice.


If you are an individual, you are known to the CMS as a client. If you already have a case with them, you can manage it online. You will be able to see if a decision has been reached and when a payment is due, or to find out how much maintenance you will need to pay. You can sign into the online portal with your Government Gateway ID, or with your personal information. If you’re having difficulty signing in or you have a question about your case, call the number above. This will put you through to Child Maintenance Options, where an operator can assist you.


As an employer, you may be asked to deduct child maintenance payments from an employee’s wages. You can use an online account to manage payments. If you have a query about how payments are deducted from wages, or you need to report that a maintenance paying employee no longer works for you, you can call the CMS Employer helpline. Calling this number means that you will speak to Child Maintenance Options, who can assist you.


Both employers and clients can use the self-service portal to deal with claims relating to the Child Maintenance Service. It is an online tool which you can log into to see when payments are due or how much is due to be deducted from an employee’s salary. You can log in with your Government Gateway ID or your personal information – however, the Government Gateway service will soon be terminated. If you require assistance with logging into the self-service portal, call the helpline. This number will get you through to the Child Maintenance Options service, who will be able to advise you on how to log in.

Disagreements about Parentage

If one party says they are not the parent of a child, the CMS will investigate. They can ask the party to provide evidence and request that both parents take a DNA test to determine parentage. The CMS may ask the court to make a decision. Parentage can also be assumed if the party was married to child’s mother between conception and birth or is named on the child’s birth certificate. The person who says they are not the parent must pay maintenance unless they can provide firm evidence that they are not. If you have any questions relating to parentage, call Child Maintenance Options for advice.

Changes in Circumstances

By law, you must tell the CMS about certain changes in circumstances. This includes: if your income increases/decreases by 25% or more, moving house, the child staying more nights with the paying parent if you change employers and if your child reaches the age of 20. The parent receiving payment is expected to tell the CMS if the child leaves full-time education. If you need to inform the CMS of a change in circumstance, call the number above. This will put you through to Child Maintenance Options, who will pass you through to the CMS.

Other Ways to Contact the CMS

You can write to the CMS at:

Child Maintenance Service
PO Box 252
GL17 1A