To file for child support in New Mexico, you apply to the Child Support Services Division (CSSD), which sits under the state’s Health Care Authority after that agency absorbed the former Human Services Department in July 2024. The application is CSSD Form 538, “Application for Full Services,” and you can submit it online through the YesNM portal at yes.nm.gov, mail a paper copy, or bring one to a regional field office.1New Mexico Human Services Department. Child Support Services Application2New Mexico Health Care Authority. Application for Full Services – CSSD Form 538 The steps below cover who can file, what to gather first, how to submit, and what happens once the agency has your case.
Who Can File in New Mexico
A custodial parent, a legal guardian, or either parent can apply. Families receiving TANF or similar public assistance are usually opened into a case automatically; for everyone else, filing is voluntary but uses the same application.
New Mexico courts can hear the case when the child or either parent lives in the state. Under the Uniform Interstate Family Support Act, adopted as Chapter 40, Article 6A, New Mexico can also assert jurisdiction over an out-of-state parent if that parent once lived here with the child, lived here and paid prenatal expenses, or if the child lives here because of something that parent did.3Justia. New Mexico Statutes Section 40-6A-201 – Bases for Jurisdiction Over Nonresident When both parents remain in New Mexico, the state keeps exclusive jurisdiction to modify the order as long as one of them stays.4Justia. New Mexico Statutes Section 40-6A-205 – Continuing, Exclusive Jurisdiction to Modify Child-Support Order
What to Gather Before You Apply
The most common reason applications stall is missing information. Collect the following before you start:
- Full legal names, Social Security numbers, and dates of birth for you, the other parent, and each child.
- The child’s birth certificate and Social Security card.
- Your federal and state tax returns for the year preceding the request and wage or payroll statements covering four months of earnings.5Justia. New Mexico Statutes Section 40-4-11.4 – Modification of Child Support Orders; Exchange of Financial Information
- Any existing custody order, divorce decree, or prior support order.
- Documentation of health insurance premiums and out-of-pocket childcare costs, both of which factor into the support calculation.
- A signed Acknowledgment of Paternity form, if one exists.6New Mexico Health Care Authority. Acknowledgement of Paternity – AOP Brochure
- Anything you know about the other parent: last known address, phone number, employer name and address, and identifying details like vehicle information.
Missing the other parent’s address or employer is not a reason to hold off. CSSD has access to state and federal databases used to locate people. Be honest on the form about what you don’t know rather than leaving fields blank.
Establishing Paternity if the Parents Weren’t Married
If the parents were married when the child was born, paternity is presumed and the agency moves straight to calculating support. If they were not married, paternity has to be established before any support order can issue.
The simplest route is an Acknowledgment of Paternity form, which both parents sign in front of a notary. Once the Bureau of Vital Records approves it, the father’s name goes on the birth certificate and legal paternity is established.7New Mexico Department of Health. Acknowledgment of Paternity If you already signed one at the hospital, have a copy ready when you file.
When paternity is disputed, CSSD can petition a court to resolve it and arrange genetic testing. The agency will advance the cost in many situations but may seek reimbursement later from the party who isn’t receiving public assistance. Federal regulations require the agency to complete service of process to begin paternity proceedings within 90 calendar days of locating the alleged father. If he doesn’t respond, the agency can ask the court for a default order.
Completing and Submitting Form 538
Form 538 asks for the demographic and financial data you gathered, plus a description of the relationship history and any prior support payments made between the parents.2New Mexico Health Care Authority. Application for Full Services – CSSD Form 538 Either parent can start it — you don’t have to be the custodial parent.
The form includes a Statement of Understanding and Notice of Non-Representation that you’ll need to read and sign. It explains that the agency represents the state’s interest in supporting the child, not either parent individually. If you want advice specific to your situation, you’d need your own attorney.
Filing through the YesNM portal gives you immediate confirmation the agency received your file. If you mail or hand-deliver instead, keep a complete copy of everything you submitted. Once the agency accepts the application, formal intake begins and your case becomes active.
Fees
Federal law caps the application fee for child support services at $25 for families not receiving public assistance. Families receiving TANF or other public assistance pay no application fee. If you apply only for payment processing rather than full enforcement services, CSSD charges a $25 annual processing fee deducted from collected support.8New Mexico Human Services Department. CSSD Form 102 / CSSD Form 538B Fact Letter
A separate federal annual user fee of $35 applies to non-assistance cases once the state has collected and disbursed at least $550 in support during a federal fiscal year. The state either passes this fee to the applicant, deducts it from collected support, or absorbs it depending on its policy.
What Happens After You File
Locating and Serving the Other Parent
After intake, the agency’s first job is notifying the other parent. Under New Mexico Rule of Civil Procedure 1-004, the non-custodial parent must be personally served with a summons and petition, meaning someone physically hands them the documents.9New Mexico Supreme Court. District Court Civil Rule 1-004 – Process Service gives them formal notice and a 30-day deadline to file a response. If the other parent ignores the summons, the agency can request a default judgment, which carries the same legal force as any other support order.
The Hearing and Final Order
If the other parent responds, the case moves toward either a stipulated agreement or an administrative hearing. When both parents agree on the numbers, they sign a stipulated order that a judge then approves. When they disagree, a hearing officer reviews the financial documentation, applies the child support guidelines, and issues a recommended order.
The final support order is legally binding and typically includes an automatic income withholding provision. New Mexico law requires the court to issue a withholding order as part of any support order, and the maximum withheld cannot exceed 50% of the paying parent’s income.10Justia. New Mexico Code 40-4A-4.1 – Immediate Child Support Income Withholding
How the Support Amount Will Be Calculated
New Mexico uses an income shares model under Section 40-4-11.1. The state estimates what both parents would have spent on the child if they lived together, then divides that cost based on each parent’s share of the combined income. The result is a rebuttable presumption — a judge can deviate, but must state the reasons in writing.
The starting point is each parent’s gross income: wages, tips, commissions, bonuses, pensions, Social Security benefits, unemployment benefits, investment income, and significant in-kind benefits that reduce living expenses. Means-tested public assistance like SNAP and child support received for other children are excluded. Alimony paid under a court order and child support paid for prior children are subtracted.5Justia. New Mexico Statutes Section 40-4-11.4 – Modification of Child Support Orders; Exchange of Financial Information
If a parent is unemployed or working below their capacity without good reason, the agency or court can impute income. Income won’t be imputed to a custodial parent actively caring for a child under six or a disabled child. Once the parents’ incomes are combined, the total is matched to the state’s Basic Child Support Schedule, then split proportionally. A parent earning 60% of the combined income pays 60% of the obligation. Health insurance premiums and childcare costs are divided the same way, and low-income payers keep a self-support reserve for basic subsistence.
When the Order Will End
Child support in New Mexico normally terminates when the child turns 18. If the child is still in high school and hasn’t yet turned 19, support continues until graduation or the 19th birthday, whichever comes first.11Justia. New Mexico Statutes Section 40-4-7 – Proceedings; Spousal Support Support can end earlier if the child marries, joins the military, or is otherwise legally emancipated.
Parents can agree in writing to continue support past high school for college or other educational expenses, and a court can enforce that agreement. Absent it, a New Mexico court generally cannot order support for an adult child’s college education on its own.