IMSS pension: Ley 73 vs Ley 97

Which law applies to you?

Workers who contributed before July 1, 1997 can choose the transition regime (Ley 73) in many cases, which usually produces a higher pension. Those who started contributing after that date are under Ley 97. The applicable law depends on your contribution history, not only on your age.

Key requirements

• The required contribution weeks (these increase progressively under the 2020 pension reform)
• Transition regime: the age and weeks required by Ley 73
• Ley 97: individual account balance plus the government guarantee
• Recognition of all contribution periods, including previous jobs

How the pension is calculated

Under Ley 73 the pension is based on the average salary of the last years of contribution and a percentage table by age and weeks. Under Ley 97 the pension depends on the accumulated balance in your individual account and the guaranteed pension. Comparing both scenarios before filing is essential.

Why the IMSS denies a pension

• Missing or unrecorded contribution weeks
• Employers that did not register the worker or reported a lower salary
• Errors in the worker's records
• Disagreement about the applicable law or the calculation

How to challenge a denial

• Request the complete contribution record and the calculation
• Correct missing weeks and salary records where possible
• File the administrative challenge and, if necessary, an amparo or labor claim

What you need

• ID and CURP
• Contribution record (semanas cotizadas)
• Pay slips and employment history
• The IMSS resolution or denial letter, if you have one

Frequent questions

Can I choose Ley 73? If you contributed before July 1997 and meet the requirements, you may be entitled to the transition regime. We verify your case.

What if my employer never registered me? The record can be corrected with evidence of the employment relationship.

How long does it take? It depends on the authority; some cases resolve in months, disputed cases can take longer.