IMSS Disability / Sick Leave Application Mexico (Solicitud de Incapacidad)

The IMSS Disability/Sick Leave Application Mexico (Solicitud de Incapacidad ante el Instituto Mexicano del Seguro Social) is the formal document used by insured workers (trabajadores asegurados) and their employers (patrones) to notify the Instituto Mexicano del Seguro Social (IMSS) of a temporary work incapacity and to activate the payment of sick leave subsidies under Articles 96 through 101 of the Ley del Seguro Social (LSS), published in the Diario Oficial de la Federación on 21 December 1995 and last reformed in 2020. When a worker registered with the IMSS becomes unable to perform their ordinary duties due to a non-occupational illness (enfermedad general), occupational illness (enfermedad de trabajo), or work-related accident (accidente de trabajo), this application triggers the medical certification process and the subsidy payment mechanism that replaces lost wages during the incapacity period.

The constitutional basis for social security in Mexico is Article 123, Apartado A, Fracción XXIX of the Constitución Política de los Estados Unidos Mexicanos, which mandates a public social security system covering illness, accidents, maternity, disability, old age, and death. The IMSS — created by the Ley del Seguro Social of 1943 and restructured under the current LSS of 1995 — administers the enfermedad y maternidad (illness and maternity) insurance branch that funds sick leave subsidies. Article 96 LSS establishes that workers suffering a non-occupational illness are entitled to a monetary subsidy (subsidio en dinero) equivalent to 60% of the worker's Salario Diario de Cotización (SDC) for each day of medically certified incapacity, beginning on the fourth calendar day of illness — the first three days constitute a waiting period (período de espera) covered directly by the employer under Article 97 LSS unless a collective bargaining agreement (contrato colectivo de trabajo) eliminates the waiting period.

For occupational risks — accidentes de trabajo and enfermedades de trabajo covered under the riesgos de trabajo branch of IMSS — the subsidy begins from the first day of incapacity under Article 58 LSS and amounts to 100% of the SDC, without any waiting period. The distinction between non-occupational and occupational incapacity is critical because it determines both the subsidy rate and the responsible IMSS branch. Employers have a legal obligation under Article 51 LSS to report workplace accidents to the IMSS within 24 hours using the Aviso de Accidente de Trabajo form, separate from the general incapacity application.

The IMSS assigns medical units (Unidades Médicas Familiares — UMFs) to each registered worker based on the employer's geographic zone. The attending IMSS physician (médico familiar adscrito) evaluates the worker's condition, determines the diagnosis, and issues the ST-7 certificate (Certificado de Incapacidad Médica para el Trabajo) — the official IMSS incapacity certificate used by both the worker and the employer to process the subsidy. The application process requires that the worker attend their assigned UMF or, in emergency cases, an IMSS hospital emergency department; the médico familiar cannot issue incapacity certificates retroactively except in documented emergency situations under IMSS administrative guidelines.

The maximum duration of subsidized incapacity for non-occupational illness under Article 101 LSS is 52 weeks (one year) from the date of onset, extendable for an additional 26 weeks if the IMSS medical committee (Comisión Médica Mixta or IMSS Dictaminador) determines that recovery is likely within that extension. If the worker remains unable to work after 78 weeks, the IMSS evaluates the condition for permanent disability (invalidez) under Articles 119 through 127 LSS, which triggers a different benefit stream — the invalidez pension rather than the temporary subsidy.

The Solicitud de Incapacidad form used at forms-legal.com captures all essential information required by the IMSS administrative process: worker identification (NSS, CURP, RFC), employer identification (Registro Patronal), treating physician and UMF details, diagnosis, dates of incapacity, and the employer's declarations regarding salary and continuation of employment. Proper completion of this form by both the worker and employer is essential for the IMSS to process the subsidy without delay and for the employer to recover the subsidy amounts through IMSS credit against quarterly quota payments (cuotas obrero-patronales).

An IMSS Disability/Sick Leave Application Mexico is required whenever a worker registered with the IMSS (trabajador asegurado) becomes temporarily unable to perform their assigned duties due to illness or injury, and the employer needs to formally document the incapacity with the IMSS to activate subsidy payments and comply with the employer reporting obligations under the Ley del Seguro Social.

The application is needed when a worker is absent from work due to a non-occupational illness (enfermedad general) that extends beyond the three-day employer-funded waiting period established by Article 97 LSS. Once the IMSS médico familiar at the worker's assigned Unidad Médica Familiar (UMF) issues the ST-7 Certificado de Incapacidad, the employer must record the incapacity and submit the related documentation so the IMSS can credit the subsidy amounts against future quota payments — or refund them directly where the employer's IMSS account balance is insufficient.

The form is required for occupational accidents (accidentes de trabajo) from the first day of incapacity, without the three-day waiting period. Under Article 51 LSS and the IMSS Reglamento de la Ley del Seguro Social en Materia de Afiliación, Clasificación de Empresas, Recaudación y Fiscalización (RACERF), the employer must submit an Aviso de Accidente de Trabajo to the IMSS within 24 hours of the accident. The incapacity application supports this notification and documents the resulting work absence for subsidy calculation purposes.

The document is needed when an employer must update payroll records to reflect the IMSS subsidy payment replacing the normal salary. Under Article 99 LSS, the IMSS subsidy (60% of SDC for general illness, 100% of SDC for occupational risk) replaces the employer's salary obligation during certified incapacity — the employer is not required to pay full salary during the IMSS-subsidized period unless the employment contract or collective agreement provides for salary top-up. Accurate documentation prevents payroll discrepancies that could trigger IMSS or SAT audits.

The application is also required when a pregnant worker invokes her maternity leave (licencia de maternidad) under Article 101 LSS — the incapacity certificate for maternity covers 42 days before and 42 days after the expected birth date (descanso pre y post natal), with the IMSS paying 100% of the SDC during the full 84-day period. The employer must process the maternity incapacity application to suspend IMSS and ISR withholdings correctly during the leave period and to document the position-preservation obligation under Article 170, Fracción II of the Ley Federal del Trabajo.

Employers with workers in the northern border free zone (Zona Libre de la Frontera Norte — ZLFN) or in states with specific IMSS regional delegations (Delegaciones del IMSS) must submit the application to the competent delegación so the subsidy calculation uses the correct Salario Diario de Cotización registered for the worker in that delegation's records.

A valid IMSS Disability/Sick Leave Application Mexico under the Ley del Seguro Social arts. 96–101 must contain the following essential elements to be accepted by the IMSS and to activate subsidy payment and employer credit procedures.

Worker Identification Data: The worker's full legal name (nombre completo), Número de Seguridad Social (NSS) assigned by IMSS upon first registration, CURP (Clave Única de Registro de Población) issued by RENAPO, RFC (Registro Federal de Contribuyentes) assigned by SAT, and the worker's home address. The NSS is the primary identifier used by IMSS to locate the worker's benefits history, contribution weeks (semanas cotizadas), and assigned medical unit (Unidad Médica Familiar). Errors in the NSS can result in the subsidy being credited to a different worker's account and must be corrected through the IMSS Sistema de Corrección de Datos before resubmission.

Employer Identification and Registro Patronal: The employer's full legal name or business name (razón social), Registro Patronal (the IMSS employer registration number assigned when the employer filed the Alta Patronal), RFC, and work centre address (domicilio del centro de trabajo). The Registro Patronal determines which IMSS Delegación Estatal processes the application and which SUA (Sistema Único de Autodeterminación) account receives the subsidy credit. Employers operating multiple work centres (centros de trabajo) under different Registros Patronales must submit the application under the specific Registro corresponding to the incapacitated worker.

Salario Diario de Cotización (SDC): The daily salary figure registered with IMSS at the time of incapacity onset. The SDC — distinct from the base salary — integrates the base daily wage plus proportional values of recurring benefits under Article 84 LFT and Article 27 LSS. The IMSS calculates the subsidy at 60% of the SDC (general illness) or 100% (occupational risk) per incapacity day. Discrepancies between the SDC registered in IMSS records and the actual SDC must be corrected through a Modificación de Salario filing (Aviso de Modificación Salarial) before the incapacity application is processed.

ST-7 Incapacity Certificate Reference: The certificate number and date of the ST-7 (Certificado de Incapacidad Médica para el Trabajo) issued by the IMSS médico familiar at the assigned UMF. The ST-7 is the controlling document — its diagnosis code (CIE-10 classification), start date, duration, and probable return-to-work date determine the subsidy period. Employers should retain a copy of the ST-7 for at least five years under Article 804 of the Ley Federal del Trabajo, as IMSS and STPS inspectors may request production during audits.

Type of Incapacity and Risk Classification: The application must identify whether the incapacity arises from enfermedad general (non-occupational illness), maternidad (maternity), accidente de trabajo (workplace accident), or enfermedad de trabajo (occupational disease). This classification determines the applicable LSS articles (Arts. 96–101 for general illness; Arts. 41–71 for occupational risk), the subsidy percentage, the waiting period applicability, and whether the employer must file a separate Aviso de Accidente de Trabajo within 24 hours under Article 51 LSS and the RACERF.

Incapacity Period and Employer Certification: The employer's certification that the worker was absent on the dates certified by the ST-7, that the employer maintained (or suspended) salary payments in accordance with Article 97 LSS, and that the employer's IMSS quota account is current (cuotas al corriente). Employers with outstanding IMSS quota debts may face delays in subsidy credits, as the IMSS applies credits against unpaid quotas before returning any balance. The IMSS Subdelegación reviews this certification when auditing the employer's Determinación Anual.

Physician and UMF Details: The name and employee number (matrícula) of the IMSS médico familiar issuing the certificate, and the number and name of the UMF to which the worker is assigned. IMSS workers with multiple employment relationships (pluriempleo) must have the UMF assignment coordinated between both employers, as the subsidy is calculated on the combined SDC from all registered employments under Article 65 LSS.

Return-to-Work or Extension Documentation: If the worker requires an extension of the incapacity period beyond the initial ST-7 duration, the application must be supplemented with a subsequent ST-7 extension certificate issued by the same or a referring IMSS physician. Extensions exceeding 26 weeks require review by the IMSS Comisión de Dictaminación (medical assessment panel) to determine whether permanent disability proceedings should be initiated under Articles 119–127 LSS.

Forms-legal.com provides this IMSS Disability Application template as a practical record-keeping and administrative tool. Every incapacity claim should be coordinated with a licensed Licenciado en Derecho specializing in seguridad social or with a certified IMSS gestión specialist to confirm compliance with current IMSS administrative guidelines, RACERF regulations, and any applicable collective bargaining agreement provisions. The IMSS Inspección, SAT, and STPS each have independent authority to audit employer incapacity and payroll records.