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Employment contracts in Mexico: indefinite by default, written terms, probation and initial training periods, fixed term limits and the 90 percent Mexican staff rule

Last verified: 2026-10-26 · Status: Stable

Any personal, subordinated and paid work creates an employment relationship in Mexico, whatever the paperwork says, and the law presumes it exists between whoever works and whoever receives the work. Contracts are indefinite unless the nature of the work justifies a fixed job or term, a season, or replacing another worker; terms must be in writing with the ten items in LFT art. 25, and the missing paper counts against the employer. A one time probation period of up to 30 days (180 days for managers and specialized professionals) or an initial training contract of up to three months (six for those roles) is allowed, and at least 90 percent of staff must be Mexican, except directors and general managers.

USD conversions use MXN 18.5026 per US dollar, the US Federal Reserve H.10 noon buying rate in New York for 16 October 2026 (FRED series DEXMXUS), the latest observation available when this page was verified. Conversions are for orientation only.

Key facts

Maximum probation period, general	30 daysLFT art. 39-A, as of 2026-10-26 · in force
Maximum probation period, management and specialized roles	180 daysLFT art. 39-A, as of 2026-10-26 · in force
Maximum initial training contract, general	3 monthsLFT art. 39-B, as of 2026-10-26 · in force
Maximum initial training contract, management and specialized roles	6 monthsLFT art. 39-B, as of 2026-10-26 · in force
Default contract type absent an express term	Indefinite LFT art. 35, as of 2026-10-26 · in force
Minimum share of Mexican workers per company or establishment	90 %LFT art. 7, as of 2026-10-26 · in force

The rule

1. An employment relationship exists whenever a person provides personal, subordinated work in exchange for a salary, whatever the act or label that gives rise to it, and the contract and the actual provision of work have the same effects. The law presumes that a contract and an employment relationship exist between the person who provides personal work and the person who receives it, so calling someone a contractor or a service provider does not by itself avoid labor obligations.Ley Federal del Trabajo (LFT), DOF 1 April 1970 (Chamber of Deputies consolidated text, last reform DOF 14 May 2026), Arts. 20 and 21, 1970-04-01 official text · verified 2026-10-26

2. Working conditions must be put in writing, in at least two copies, when no collective agreement applies. The document must state: the identity, nationality, age, sex, marital status, CURP, RFC and address of worker and employer; whether the relationship is for a specific job or term, a season, initial training or indefinite, and whether it is subject to probation; the services, with as much precision as possible; the place or places of work; the length of the working day; the form and amount of salary; the day and place of payment; the commitment to train the worker; other conditions such as rest days and vacations; and the beneficiaries for wages owed on the worker's death. If there is no written contract, the worker keeps every legal right and the missing formality is attributed to the employer.
Cost to do it: No government fee to sign an individual employment contract; the cost is drafting time or legal fees.Ley Federal del Trabajo (LFT), DOF 1 April 1970 (Chamber of Deputies consolidated text, last reform DOF 14 May 2026), Arts. 24, 25 and 26, 2019-05-01 official text · verified 2026-10-26

3. Indefinite is the default. Relationships may be for a specific job or term, by season or indefinite, and may include probation or initial training; without an express term the relationship is indefinite. A specific job may only be agreed when its nature requires it, and a fixed term only when the nature of the work requires it, to temporarily replace another worker, or in other cases the law provides. If the term expires but the work continues, the relationship is extended for as long as that remains the case. Indefinite relationships may be agreed as discontinuous for fixed, periodic work such as seasonal activities, with rights in proportion to time worked. Workers may never be obliged to serve for more than one year.Ley Federal del Trabajo (LFT), DOF 1 April 1970 (Chamber of Deputies consolidated text, last reform DOF 14 May 2026), Arts. 35, 36, 37, 39, 39-F and 40, 2012-11-30 official text · verified 2026-10-26

4. Probation: in indefinite relationships, or those longer than 180 days, a probation period of up to 30 days may be agreed solely to check that the worker meets the requirements of the job; it may be extended up to 180 days only for management, administration and direction positions or specialized technical or professional work. During probation the worker receives the salary, social security and benefits of the position. If, in the employer's judgment and taking into account the opinion of the joint productivity and training committee, the worker does not meet the requirements, the relationship ends without liability for the employer.
Cost to do it: Salary, social security and benefits accrue in full during probation; ending it validly costs only accrued pay and proportional benefits.
Example: An engineer hired at MXN 45,000 a month (MXN 1,500.00 a day) with a 180 day probation is let go at day 180: no severance, but the proportional year end bonus (15 days x 180/365, MXN 11,095.89) and proportional vacation of 12 days with the 25 percent premium (MXN 8,876.71 plus MXN 2,219.18) are owed, MXN 22,191.78 in total. / About USD 1,199 at 18.5026 (monthly salary about USD 2,432).Ley Federal del Trabajo (LFT), DOF 1 April 1970 (Chamber of Deputies consolidated text, last reform DOF 14 May 2026), Art. 39-A, 2012-11-30 official text · verified 2026-10-26

5. Initial training contracts: a worker may be hired for initial training, to acquire the knowledge or skills for the job, for up to three months, or up to six months for management, administration and direction positions or work requiring specialized professional knowledge, with full salary, social security and benefits. Probation and initial training must be agreed in writing with social security guaranteed, otherwise the relationship is deemed indefinite. Both periods cannot be extended, and they may not be applied to the same worker more than once in the same company, simultaneously or successively, even for a different position, a promotion or a later rehiring. If the relationship continues afterwards it is indefinite and the period counts toward seniority.Ley Federal del Trabajo (LFT), DOF 1 April 1970 (Chamber of Deputies consolidated text, last reform DOF 14 May 2026), Arts. 39-B, 39-C, 39-D and 39-E, 2012-11-30 official text · verified 2026-10-26

6. At least 90 percent of the workers in every company or establishment must be Mexican. Technicians and professionals must be Mexican unless none are available in a given specialty, in which case foreign workers may be hired temporarily up to 10 percent of that specialty, and the employer and the foreign workers must jointly train Mexican workers in it. Company doctors must be Mexican. The rule does not apply to directors, administrators and general managers.Ley Federal del Trabajo (LFT), DOF 1 April 1970 (Chamber of Deputies consolidated text, last reform DOF 14 May 2026), Art. 7, 1970-04-01 official text · verified 2026-10-26

7. Any waiver by workers of earned wages, compensation or other benefits is void, whatever its form. Every settlement or termination agreement must be in writing, describe the facts and the rights it covers, and be ratified before the Conciliation Center or the labor court, which approves it if it contains no waiver of rights. An agreement signed without the authorities remains valid except for any clause that waives rights, which the worker can ask the court to annul.Ley Federal del Trabajo (LFT), DOF 1 April 1970 (Chamber of Deputies consolidated text, last reform DOF 14 May 2026), Art. 33, 2019-05-01 official text · verified 2026-10-26

Type	When allowed	Maximum length	Source
Indefinite	Default; also continuous or discontinuous (seasonal) work	None	LFT arts. 35 and 39-F
Specific job (obra determinada)	Only when the nature of the work requires it	Until the job ends; extended while the work subsists	LFT arts. 36 and 39
Fixed term (tiempo determinado)	Nature of the work, temporary replacement, or other legal cases	Agreed term; extended while the work subsists	LFT arts. 37 and 39
Probation within an indefinite contract	Indefinite contracts or contracts over 180 days, in writing	30 days; 180 for management and specialized roles; once only	LFT arts. 39-A, 39-C and 39-D
Initial training	To acquire the skills for the job, in writing	3 months; 6 for management and specialized roles; once only	LFT arts. 39-B to 39-D

Contract types under the Ley Federal del Trabajo, verified 26 October 2026.

Worked example

A US company's Mexican subsidiary hires a software engineer in Guadalajara on an indefinite contract at MXN 45,000 a month (about USD 2,432), with a 180 day probation because the role is specialized, and a written contract covering the items in LFT art. 25.
It registers the engineer with IMSS within five business days of hire (LSS art. 15) and pays full salary and benefits during probation.
If the engineer does not meet the requirements at the end of probation, the relationship may end without severance, paying the accrued proportional year end bonus and vacation (about MXN 22,192, USD 1,199); if the engineer stays, the contract becomes indefinite and the 180 days count toward seniority.
The company may not later place the same engineer on a new probation or training period, even for a promotion.

Step by step

1. Decide the contract type before the offer: indefinite unless a fixed job, term or season genuinely applies (LFT arts. 35 to 37).
2. Draft the written contract in Spanish with every item of LFT art. 25, including beneficiaries, and give one signed copy to the worker.
3. If you use probation or initial training, write it into the contract with the length and the position, and record the opinion of the joint training committee before ending it (LFT arts. 39-A to 39-C).
4. Register the worker with IMSS and INFONAVIT within five business days of hire (LSS art. 15).
5. Check the 90 percent Mexican staff ratio by establishment when hiring foreign technicians, and arrange immigration status first (see the immigration section).
6. Document any termination or settlement in writing and ratify it at the Conciliation Center (LFT art. 33).

Common traps

Rolling fixed term contracts. A fixed term is only valid for the cases in LFT art. 37 and, if the work continues after expiry, the relationship is extended by law (art. 39).
A second probation. Probation and initial training can be used once per worker per company, never again for a new position, promotion or rehire (LFT art. 39-D).
Unwritten probation. A probation or training period not put in writing makes the relationship indefinite from day one (LFT art. 39-C).
Contractor labels. A services agreement does not prevent a court from finding employment where work is personal and subordinated (LFT arts. 20 and 21).
Unratified releases. A resignation or settlement that waives rights is void as to that waiver; ratification before the Conciliation Center protects the employer (LFT art. 33).

Sources

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