Replacement of the IMSS Digital Certificate with the e.firma for Electronic Procedures
Replacement of the IMSS Digital Certificate with the e.firma for Electronic Procedures
New provision applicable as of October 14, 2026
The Mexican Social Security Institute (IMSS) published Agreement ACDO.AS2.HCT.290626/176.P.DIR in the Official Gazette of the Federation on July 16, 2026. Under this Agreement, the IMSS eliminates the use of the Electronic Employer Identification Number (NPIE) and its digital certificate and establishes the Advanced Electronic Signature (e.firma) issued by the Mexican Tax Administration Service (SAT) as the sole authentication mechanism for conducting electronic procedures before the Institute.
What does this change mean?
Employers that currently use the IMSS digital certificate to carry out electronic procedures will be required to migrate to the use of a valid e.firma issued by the SAT.
As of October 14, 2026, the e.firma will be required for, among others, the following procedures:
- Employee registrations.
- Employee terminations.
- Salary modifications.
- Other electronic procedures and filings before the IMSS that require authentication.
The digital certificate associated with the NPIE, commonly used to carry out electronic procedures before the IMSS, will no longer be used.
The IMSS has granted a 90-calendar-day transition period, beginning on the date the Agreement was published, for employers to migrate to the new scheme. Therefore:
Publication date: July 16, 2026
Start of transition period: July 17, 2026
Deadline to complete the migration: October 13, 2026
As of: October 14, 2026, the e.firma must be used exclusively in accordance with the new provisions.
What should you do as an employer registered with the IMSS?
To avoid disruptions to payroll operations and the filing of employee registration and affiliation movements with the IMSS, we recommend taking the following actions in a timely manner:
1. Verify that the company’s e.firma is valid and up to date.
2. Verify that the legal representative’s e.firma is valid and up to date.
3. Link both e.firmas through the IMSS Virtual Desktop (Escritorio Virtual del IMSS).
4. Have the following supporting documentation readily available:
- Valid company e.firma.
- Valid e.firma of the legal representative.
- Valid official identification of the legal representative.
- Current articles of incorporation.
- Valid power of attorney.
- Employer Identification Card (Tarjeta de Identificación Patronal – TIP) / available IMSS employer documentation.
- The information and access credentials required for the IMSS Virtual Desktop.
If the company does not complete the transition in a timely manner and does not have the required e.firmas and linkages in place, it may encounter difficulties when carrying out employee affiliation movements electronically before the IMSS, including employee registrations, terminations, and salary modifications.
This could result in delays in payroll processes and affect the timely fulfillment of social security obligations.
For this reason, we recommend not waiting until the deadline to complete the migration process.
The BSO team at BDO Mexico is at your disposal to provide support and guidance in complying with this new obligation.