IMSS Mexico

Mexico Consulting takes care of IMSS matters for international clients in the largest construction projects in Mexico.

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Our experts will to assist you with questions regarding the IMSS and its requirements.



The Mexican Social Security Institute (IMSS) is a decentralized agency of the Mexican federal government. The Social Security Institute is abbreviated with the acronym IMSS. The IMSS is provides health and social security services to the population. There are numerous obligations for companies to meet with the IMSS.

IMSS Mexico

A look inside

Companies that carry out construction activities are particularly affected by obligations to the IMSS (Instituto Mexicano del Seguro Social).

The requirements are constantly changing. Reforms such as REPSE bring additional challenges.



Companies in the construction industry are obliged to register with SIROC (Integral Registration Service for Construction Work) and apply for the REPSE number. In some cases, the contracting company requires a correction. In these cases, a “Corrección Patronal” is requested. The correction is completed with the so-called “Oficio de Conclusión”.









IMSS Mexico

IMSS Mexico Construction


Registro de Prestadoras de Servicios Especializados u Obras Especializadas

REPSE stands for “Registration of Specialized Service Providers or Specialized Work” (Registro de Prestadoras de Servicios Especializados u Obras Especializadas). As part of the Mexican labor market reform, there was a ban on outsourcing. REPSE is designed to ensure that this outsourcing ban cannot be circumvented. Since the labor market reform, it is no longer permitted in the construction industry to employ subcontractors to provide the same services. In practice, this means that a company offering insulation work, for example, may not contract subcontractors who also offer insulation work. This causes difficulties, especially for larger projects with high personnel requirements.

REPSE number

  • This is the “Register of Specialized Service Providers or Specialized Works” /Registro de Prestadoras de Servicios Especializados u Obras Especializadas), which is maintained on the online platform of the Ministry of Labor and Social Affairs.
  • Natural and legal persons could obtain their registration and entry in the register of specialized services.


Servicio Integral de Registro de Obras de Construcción


SIROC stands for “Integral Registration Service for Construction Works” (Servicio Integral de Registro de Obras de Construcción). The objective is to ensure the company’s compliance with the requirements of the IMSS.

Obligated to SIROC are:


  • Owners of construction sites that hire workers involved in these works, either directly or through intermediaries.
  • Persons and companies contracted by owners to perform construction work at a lump sum price or under the unit price system with workers at their disposal.
  • Natural or legal persons who are subcontracted to perform part or parts of the work.

Once the work has been completed, the so-called “Opinión del Cumplimiento de Obligaciones Fiscales en materia de Seguridad Social” (Statement of Compliance with Social Security Tax Obligations) confirms that the company has complied with all social security obligations at the time of application. However, in some cases this is not sufficient and the “Oficio de Conclusión” is required.



Presentación de la corrección patronal ante el IMSS

Particularly in the case of large projects sometimes the client wishes to obtain additional security. In this case, a “correction” (Corrección Patronal ante el IMSS) is requested. Despite full payment of all social security contributions, the IMSS checks numerous documents and demands payment as part of this correction. The submission is made with the so-called form CORP 02.

Form CORP 02 must be submitted to IMSS with the following documentation:


  • Proof of submission of the declarations that are the reason for the correction.
  • Proof of payment or, if applicable, deferral of payment or payment by installments of the established differences.
  • Trial balance with balances by fiscal year and for the subperiod.
  • Payroll with balances by fiscal year and for the subperiod.
  • Receipts or vouchers for payroll.
  • Proof of timely payment of employer contributions.
  • Annual income tax return for the tax year.
  • Income from honoraria for individuals and from honoraria equivalent to salaries.
  • Collective or individual employment contract.

Oficio de Conclusión

Completion of “corrección patronal” with “oficio de conclusión”.

The documents are reviewed by the IMSS. In case the documents have not been prepared properly, the process can take many months. In some cases, numerous on-site meetings at the relevant IMSS office are necessary. After thorough examination and clarifications, the claimed amounts must be paid. Subsequently, the official proof is issued. The official proof is called “Oficio de Conclusión”. Only this “Oficio de Conclusión” will be accepted by the client as proof that there will be no further claims from the IMSS.

The IMSS has numerous offices in Mexico. Therefore, both closing requirements and back payments may differ at each local IMSS office.

Careful preparation of all documentation according to the specific requirements of the IMSS offices is the basis for successful negotiations and timely closing.


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