In the 1940s, curbing undocumented Mexican immigrant entry into the United States became a US government priority because of an alleged immigration surge, which was blamed for the unemployment of an estimated 252,000 US domestic agricultural laborers. Publicly committed to asserting its control of undocumented Mexican immigrant entry, the US government used Operation Wetback, a binational INS border-enforcement operation, to strike a delicate balance between satisfying US growers’ unending demands for surplus Mexican immigrant labor and responding to the jobs lost by US domestic agricultural laborers. Yet Operation Wetback would also unintentionally and unexpectedly fuel a distinctly transnational pathway to legalization, marriage, and extended family formation for some Mexican immigrants.On July 12, 1951, US president Harry S. Truman’s signing of Public Law 78 initiated such a pathway for an estimated 125,000 undocumented Mexican immigrant laborers throughout the United States. This law was an extension the Bracero Program, a labor agreement between the Mexican and US governments that authorized the temporary contracting of braceros (male Mexican contract laborers) for labor in agricultural production and railroad maintenance. It was formative to undocumented Mexican immigrant laborers’ transnational pursuit of decisively personal goals in both Mexico and the United States.Section 501 of this law, which allowed employers to sponsor certain undocumented laborers, became a transnational pathway toward formalizing extended family relationships between braceros and Mexican American women. This article seeks to begin a discussion on how Operation Wetback unwittingly inspired a distinctly transnational approach to personal extended family relationships in Mexico and the United States among individuals of Mexican descent and varying legal statuses, a social matrix that remains relatively unexplored.