The Mexican Institute of Social Security has moved to a unified digital authentication system, requiring all employers to use the Tax Authority’s electronic signature for every procedure.
Published in the Official Gazette of the Federation on July 16, 2026, the agreement formally establishes the e.firma as the only valid credential for IMSS interactions.
The agreement, referenced as ACDO.AS2.HCT.160726/3.P.DIR, is the result of a broader transition process designed to fully digitalise all IMSS administrative processes.
Under the new rules, the e.firma will serve as the sole certificate for authenticating an employer’s identity across all procedures conducted with the institute.
Legal representation of a company must now be managed through the IMSS Virtual Desktop, using the legal representative’s company e.firma to gain access.
The transition also means the IMSS digital certificates will no longer exist, effectively retiring the Employer Electronic Identification Number, known as the NIPE.
A range of critical employer procedures will be affected, including affiliation movements such as enrollments, cancellations, and salary modifications, as well as risk premium determination.
Payment receipts for social security contributions and access to the IMSS mailbox are among the other processes impacted by the new authentication requirements.
Employers have been granted a ninety-day transition period, with the deadline falling on October 14, 2026, to adopt the e.firma and avoid potential fines.
During this period, businesses are advised to verify that both the company e.firma and the legal representative’s e.firma are active and properly linked to the Employer Registration Number at the IMSS Virtual Desktop.
It is essential that the employer’s representative holds a duly updated e.firma, as the system linkage cannot be properly executed without a valid and current credential.
Employers who fail to complete the transition within the allotted timeframe risk non-compliance penalties that may extend beyond the authentication issue itself to other outstanding obligations.
The changes represent a significant administrative shift for businesses operating in Mexico, requiring prompt action from compliance and human resources teams ahead of the October deadline.