Articles 24 and 25 of Mexico’s Federal Labor Law require working conditions to be set down in writing. Article 26 states: “La falta del escrito a que se refieren los artículos 24 y 25 no priva al trabajador de los derechos que deriven de las normas de trabajo y de los servicios prestados, pues se imputará al patrón la falta de esa formalidad.”
In other words, a worker without the written document keeps all rights, and the missing paper counts against the employer.
According to INEGI’s employment survey, as reported by the Mexico Solidarity Project, 41.4 percent of subordinate workers had no written contract in February 2026.