Mexico's annual tax declaration with the SAT
The declaracion anual is the annual income tax return that certain individuals in Mexico file with the Servicio de Administracion Tributaria — the SAT — covering the previous calendar year. For most individuals (personas fisicas) who are required to file, the general deadline falls in April of the following year. Whether you need to file, and how, depends on your income sources and whether your employer has handled withholding throughout the year. A qualified tax professional (contador publico) can clarify your specific obligations.
What the SAT is and the role of the RFC
The SAT (sat.gob.mx) is Mexico's federal tax authority, responsible for administering and collecting federal taxes including income tax (Impuesto Sobre la Renta, or ISR) and value-added tax (IVA).
Every individual or entity with tax obligations in Mexico must have an RFC — Registro Federal de Contribuyentes. This unique tax identification number is assigned by the SAT and appears on all tax filings, invoices (facturas), and official correspondence. If you do not already have an RFC, the SAT allows registration through its website or in person at a local office (Modulo de Servicios Tributarios).
The RFC consists of:
- Four letters derived from your full name and date of birth
- Six digits representing your date of birth
- Three alphanumeric characters (the homonimia) that distinguish individuals with identical base codes
Keeping your RFC registration up to date — including your current address and activity codes — is a prerequisite for filing correctly.
Who must file the declaracion anual
Not every employed individual in Mexico is required to file an annual return. Withholding by employers handles the tax obligation for many salaried workers throughout the year. However, filing is generally required if you:
- Received income from two or more employers in the same year
- Earned interest income above the threshold set annually by the SAT
- Received dividends or profit distributions
- Had income from professional fees (honorarios) or self-employment activity
- Obtained income from leasing property (arrendamiento)
- Had income from the disposal of real estate or shares
- Are voluntarily filing to claim a balance in your favour (saldo a favor) — for example, due to deductible personal expenses (deducciones personales)
Employees with a single employer who withheld correctly throughout the year may still choose to file voluntarily if they have claimable deductions. The SAT's portal pre-populates information from CFDI (electronic invoices) and employer declarations, which simplifies the process.
The SAT portal and how to file
The SAT operates an online portal at sat.gob.mx where individuals can complete and submit the declaracion anual. Accessing the portal requires:
- Your RFC
- Your RFC password (Contrasena) or the advanced e.signature (e.firma, formerly FIEL) — a digital certificate issued by the SAT on a USB token
Steps in the online filing process:
- Log in at sat.gob.mx with RFC and password or e.firma
- Navigate to Declaraciones > Anuales > Personas Fisicas
- Select the tax year and the applicable income regime
- Review pre-populated data drawn from CFDI records and employer submissions
- Enter additional income, deductible expenses, and any supplementary information
- Submit and download the acknowledgement (acuse de recibo)
The SAT also offers in-person assistance at its local offices for filers who need help using the portal or who have complex situations.
The general April deadline for individuals
The SAT sets the general deadline for individuals (personas fisicas) to file the declaracion anual in April of the year following the tax year. The exact date is confirmed annually by the SAT in its official communications and on sat.gob.mx — consult the authority directly for the current year's deadline.
Key points about the deadline:
- Filing electronically through the SAT portal is the standard channel; paper filing is no longer routinely available for most taxpayers
- Interest charges and surcharges (recargos) apply to late payments of any tax due
- A balance in your favour (saldo a favor) can be requested as a refund through the same portal, and the SAT processes approved refunds by bank transfer to a registered account
Deducciones personales: what individuals can deduct
The ISR law permits certain personal deductions that reduce taxable income when filing the annual return. These include categories such as medical and dental fees, hospital expenses, funeral expenses, mortgage interest, and voluntary pension contributions, among others. The specific items, limits, and documentary requirements are defined by the SAT and updated periodically — the authority publishes the current rules at sat.gob.mx.
To support deductions, expenses must generally be supported by a valid CFDI (electronic invoice) linked to your RFC. Expenses paid in cash above the limit specified by the SAT may not be deductible.
A tax professional can help identify which deductions apply to your situation and ensure the supporting documentation meets SAT requirements.
Where to get help
For current filing deadlines, portal access, and official guidance, visit the SAT at sat.gob.mx. To find a qualified tax professional (contador publico) in Mexico, visit the Mexico tax professional directory.
Sources
- Servicio de Administracion Tributaria (SAT): sat.gob.mx