Understanding Mexican Naming Conventions to Decode Mexican ID Numbers

In Mexico, the composition of ID numbers is heavily tied to the subject’s name. The national ID number (CURP), tax ID number (RFC), and voter ID number all rely on letters from the given name, paternal surname, and maternal surname. It is important to be able to identify these three parts in order to understand ID number construction and identify false ID numbers.

In Spanish-speaking Latin America, names are comprised of three parts:

  • Given name (either a single name like Alejandra or, more commonly, a compound name with two or more names like Francisco Enrique)
  • Paternal surname (can be compound, but this is less common)
  • Maternal surname (can be compound, but this is less common)

For example, a person with the full legal name Juan Carlos Hernandez Garcia has Juan Carlos as the given name, Hernandez as the paternal surname, and Garcia as the maternal surname.

A more in-depth discussion of naming conventions in Spanish and Portuguese-speaking Latin America can be found here.

What ID Numbers Leave Out

José and María are popular given names in Mexico that are usually combined with other names to form a compound given name like José Antonio or María Teresa. These names are sometimes abbreviated in public records with José abbreviated as J or J. and María abbreviated as Ma or Ma. Because José and María are so common, they are often ignored in ID number construction and the other names within the compound given name are used instead. 

The words de and del (meaning “of” and “of the”) as well as the words los, las, el, and la (all meaning “the”) are sometimes incorporated into compound given names like in María de los Ángeles and José de Jesus. They can also be incorporated into compound paternal and maternal surnames. The words de, del, los, las, el, and la are all ignored when constructing these three types of ID numbers. Other languages’ equivalents of these words are also ignored including da, du, das, der, di, die, les, le, van, and von.

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