CURP is the abbreviation for Clave Única de Registro de Población (translated into English as Unique Population Registry Code or else as Personal ID Code Number). It is a unique identity code for both citizens and residents of Mexico.
Each CURP code is a unique alphanumeric 18-character string intended to prevent duplicate entries into the system. The CURP Card is needed to obtain most government services in Mexico. You can obtain one by presenting your original and a copy of your immigration (Permanent or Temporary) visa, along with your passport and a copy of the page within your passport showing your photo and date of issuance. You cannot use a Tourist Visa to apply for a CURP Card. A list of government offices where you can obtain a CURP Card can be accessed by clicking here.
Currently the CURP is essential for tax filings, to keep records of companies, schools, membership in government-run health services, passport applications, and other government services. The CURP number is now used in all Civil Registry individual records (birth and death certificates) and certified copies of them.
Initally, the CURP card (cédula) was available at CURP government offices or at the Civil Registry, ISSSTE, IMSS and other government services. The document was printed on green paper, but today are printed on white paper and often laminated. In fact you can print a valid copy of existing CURP documents at visiting the official website – http://consultas.curp.gob.mx/CurpSP/. The CURP card is 5.4 cm wide and 8.6 cm long (2.125 in x 3.4 in), fitting in most wallets. The front of the card gives the CURP 18-character string, given names and surnames, plus the date of registration and a folio number. The back contains information referencing the document used as proof to originally assign the CURP code (if it was a birth certificate, folio number and issuing municipality and a barcode.
The use of CURP cards begin on October 23, 1996, with the Presidential Agreement for the Adoption and Use of the Population Registry Unique Code by the Federal Government (Acuerdo Presidencial para la adopción y uso por la Administración Pública Federal de la Clave Única de Registro de Población) was published in the Official Gazette of the Federation. The Agreement provides assigning a CURP number to everyone living in Mexico and to Mexicans living abroad.
How CURP Codes are Constructed
To understand how CURP codes are built, one must first understand Hispano-American naming conventions. Full names in Spanish-speaking countries (including Mexican full names) consist of three elements:
First surname: the father’s first surname; and
Second surname: the mother’s first surname.
The CURP code is composed of 18 characters that are assigned as follows:
The first surname’s initial and first inside vowel;
The second surname’s initial (or the letter “X” if, like some foreign nationals, the person has no second surname);
The first given name’s initial;
Date of birth (2 digits for year, 2 digits for month, and 2 digits for day);
A one-letter gender indicator (H for male (hombre in Spanish) or M for female (mujer in Spanish));
A two-letter code for the state where the person was born; for persons born abroad, the code NE (nacido en el extranjero) is used;
The first surname’s second inside consonant;
The second surname’s second inside consonant;
The first given name’s second inside consonant; and
Two characters ranging from 1-9 for people born before 2000 or from A-Z for people born since 2000; these characters are generated by the National Population Registry to prevent identical entries.
For married women, only maiden names are used.
For example, the CURP code for a hypothetical person named Gloria Hernández García, a female, born on 27 April 1956 in the state of Veracruz, could be HEGG560427MVZRRL05.
Several exceptions to the above rules exist, including:
“Ñ” – If any step in the above procedure leads to the letter “Ñ” appearing anywhere in the CURP, the “Ñ” is replaced by an “X”.
Very common given names
When a person has two given names and the first given name is Maria, as is often the case for women in Mexico, or José, in the case of men, the first name will be overlooked and the fourth character will be taken from the second given name’s initial. This is because the names María and José are very common and would generate many duplicates if used to generate the code. For example, if the person were named María Fernanda Escamilla Arroyo, her CURP’s first four characters would be ESAF because María does not count for the CURP’s fourth character when a second given name is present.
Catalog of Inappropriate Words
To prevent words from forming that would be deemed palabras altisonantes (foul-sounding words, such as profanity or pejoratives) in the first four characters of the string, a Catalog of Inappropriate Words (Catálogo de Palabras Inconvenientes) lists many such possible combinations and provides replacements that usually entail changing the second letter, a vowel, into an “X”.
Outside Mexico City, the Clave de Registro e Identidad Personal (Personal Registration and Identification Code) is used, in addition to CURP.