People who stopped contributing to the Instituto Mexicano Del Seguro Social can still keep building retirement weeks through Modalidad 40, the voluntary continuation scheme known formally as Continuación Voluntaria en el Régimen Obligatorio. In June 2026, the practical question for former insured workers is not whether the option exists, but whether they still fit the enrollment window and the contribution rules that shape what they will pay.
To register, applicants must have been discharged from the IMSS obligatory regime, have at least 52 credited weeks in the five years before that discharge, and file the request within 12 months after the labor relationship ended. The process can be completed online or in person, and the online route begins in the IMSS portal, where the person enters personal data and selects the Salario Base de Cotización used for contributions.
That salary choice matters because it sets the monthly payment, but it is not unlimited. The selected base cannot fall below the last registered salary before discharge, and it cannot rise above 25 times the current value of the Unidad de Medida y Actualización. The amount due also depends on the contribution rates in force under the Ley del Seguro Social, so two people in the same scheme can face very different monthly bills.
IMSS Modalidad covers two parts of the system: Seguro de Invalidez y Vida and Seguro de Cesantía en Edad Avanzada y Vejez. The insured person pays those premiums in full. After approval, IMSS issues the payment format so coverage can begin, and people who apply online are notified of the result within five business days. In person, the applicant must go to the IMSS subdelegation that corresponds to them with a current official identification, a free-form written request for registration in Modalidad 40, and proof of address no older than three months.
The scheme is more than a paperwork option for people who are no longer working for a company. It is the mechanism that lets former contributors keep adding weeks toward retirement and, through a higher chosen base, improve the calculation of a future pension. The 2020 reform still shapes the cost of that decision because it introduced gradual increases in contributions for the Cesantía en Edad Avanzada y Vejez branch, with those changes set to continue through 2030.
What remains open is not eligibility, but the final bill. The rules make clear who can enter Modalidad 40 and how to choose a salary base, yet the monthly amount is different in every case because it turns on the last registered salary, the UMA ceiling, and the contribution rates that apply at the moment the request is filed. For anyone leaving formal work now, that calculation is the first real test of whether staying in the system is affordable.
