Your friend is NOT a citizen, simply by virtue of having a U.S. citizen father. However, he may be a citizen if his father registered his birth with the U.S. State Dept. within two years of his birth. This could have been done at the U.S. Consulate in Mexico, or upon returning to the U.S. If his father did not register him in infancy, then the fastest way to citizenship depends on a couple of things. If your friend is under the age of 21, and unmarried, then he is still a "child" of a USC and his father can file papers for him to obtain lawful permanent residence quite quickly as an "immediate relative" of a USC. If he is over 21, or married, then he is not longer a "child" (for immigration purposes); as the adult son of a USC, he is still elligible for Lawful Permanent Residence (a green card), but it will take much longer. He would fall into the 3rd category of "family preference" quotas. The wait for an immigrant visa for 3rd preference relatives from Mexico is 13 to 14 years! (According to the monthly Visa bulletin published by the USCIS, they are currently processing 3rd preference visas for Mexicans that were filed on Jan. 01, 1992.) In either case, your friend will have to wait five years after obtaining LPR status before he can "naturalize" to become a USC. At that time, he will have to pass a (simple) test on American history, demonstrate proficiency in the English language, and show that he is of "good moral character" -- which means he better not have any police record, especially for something like drugs! Only an immigration specialist can examine your friend's particular circumstances and guide him in the best way to secure his citizenship. And be careful! (Lots of folks will take his money, but they might not really know how to help him.)

The above answer is just plain false. Your friend's citizenship status does NOT depend on whether his father registered his birth within two years or not. Your friend is probably already a citizen, as I explain below. The issue isn't how to become a citizen, it's how to prove that he already is one. Once he's done that he can obtain a US passport. If his father did register his birth, that will certainly make it simpler; he probably only needs his birth certificate to apply for a US passport, like any other US citizen. If his birth wasn't registered, it's a bit more complicated. He has to prove to US authorities' satisfaction that his father was a US citizen and met the conditions for transmitting citizenship at his birth (see below). If his father is still around, that shouldn't be a problem. If not, your friend will need to gather some documentary evidence -- he needs to go a US consulate, explain the situation, and ask for further guidance. Remember, though, he should be working on the basis of already being a US citizen and just having to prove it, rather than of trying to acquire citizenship. Now, here are the conditions -- the *only* conditions -- that affect whether he is a citizen or not: Your friend's father was born in the USA and is/was therefore a US citizen. In general, a US citizen parent automatically transmits US citizenship to his or her offspring. The *only* condition is that the parent must have lived for a certain minimum time in the US before having the child in question. This is to prevent an endless chain of US citizen descendents none of whom have any actual connection to the USA. The amount of time depends on when your friend was born. Since 1986, it's been five years. In other words, if his father lived in the USA for at least five years *any time* before he was born, then your friend is already a US citizen by birth. Oh -- at least two of those years have to have been after his father reached his 14th birthday. So, for instance, if your friend's father was born in the US but left before he was 16, and never went back, then your friend wouldn't be a citizen. Outside of that scenario, though, he should be OK. If your friend was born before 1986 the relevant time period is longer -- I think the parent has to have lived in the US at sometime in his life for at least 10 years, at least 5 after age 14. The principle is the same, though.

If his father was in Mexico when your friend was born, yes, your friend can request American citizenship on the grounds of "son of an American born out of the USA. We did that with my son. He has both citizenships. This must be done thru an American Consulate, and his father will no doubt have to be present. They will request a LOT of documentation. On the other side of the spectrum, if a child is born in the USA, and has at least 1 parent who was born in Mexico, the child may obtain Mexican citizenship through naturalization. What is the cheapest and quickest way to do that? See the website: http://mexican-citizenship-now.tripod.com

That depends. Was his Dad a citizen of the US at his birth? Was his paternity proven/accepted? and Was his foreign birth recorded as a foreign birth of a US citizen? If answer to all these is "yes" then he is a citizen. If no, then he is not. The birth of a child abroad to U.S. citizen parent(s) should be reported as soon as possible to the nearest American consular office for the purpose of establishing an official record of the child’s claim to U.S. citizenship at birth. The official record is in the form of a Consular Report of Birth Abroad of a Citizen of the United States of America. This document, referred to as the Consular Report of Birth or FS-240, is considered a basic United States citizenship document. An original FS-240 is furnished to the parent(s) at the time the registration is approved. REPORTING THE BIRTH A Consular Report of Birth can be prepared only at an American consular office overseas while the child is under the age of 18. Usually, in order to establish the child’s citizenship under the appropriate provisions of U.S. law, the following documents must be submitted: (1) an official record of the child’s foreign birth; (2) evidence of the parent(s)’ U.S. citizenship (e.g., a certified birth certificate, current U.S. passport, or Certificate of Naturalization or Citizenship); (3) evidence of the parents’ marriage, if applicable; and (4) affidavits of parent(s)’ residence and physical presence in the United States. In certain cases, it may be necessary to submit additional documents, including affidavits of paternity and support, divorce decrees from prior marriages, or medical reports of blood compatibility. All evidentiary documents should be certified as true copies of the originals by the registrar of the office wherein each document was issued. A service fee of $65 is prescribed under the provisions of Title 22 of the Code of Federal Regulations, Section 22.1, item 9, for a Consular Report of Birth. NOTE: Consular Reports of Birth are not available for persons born in Puerto Rico, the U.S. Virgin Islands, the Panama Canal Zone before October 1, 1979, the Philippines before July 4, 1946, American Samoa, Guam, Swains Island, the Commonwealth of the Northern Mariana Islands, or the former U.S. Trust Territories of the Pacific Islands. Birth certificates for those areas, except the Panama Canal Zone, must be obtained from their respective offices of vital statistics. Panama Canal Zone birth certificates should be requested through the Vital Records Section of Passport Services (see address below.) The fees are the same as those for DS-1350. DOCUMENTS AVAILABLE Consular Report of Birth (FS-240) On November 1, 1990, the Department of State ceased issuing multiple copies of the Consular Report of Birth (FS-240). As of that date, a new format for the FS-240 went into effect. All previously issued FS-240s are acceptable proof of U.S. citizenship (Public Law 97-241 - Aug. 24, 1982). To obtain a replacement for a lost or mutilated document, please submit a notarized written request including the original FS-240 or a notarized affidavit concerning the loss of the FS-240 and a $30 fee, payable to the “Department of State.” Mail it to the address below. The affidavit must contain the: 1) name, (2) date, and (3) place of birth of the subject; (4) a statement regarding the whereabouts of the original FS-240; and (5) be signed by the subject, parent, or legal representative. Certification of Report of Birth (DS-1350) If the birth was recorded in the form of a Consular Report of Birth, a Certification of Report of Birth (DS-1350) can be issued in multiple copies. The DS-1350 contains the same information as that on the new format Consular Report of Birth and is acceptable for all legal purposes. The DS-1350 is not issued overseas and can be obtained only by writing to the address below. AMENDING/CORRECTING THE CONSULAR REPORT OF BIRTH To amend or correct a Consular Report of Birth, submit a written request - accompanied by certified copies of all documents appropriate for effecting the change (e.g., foreign birth certificate, marriage certificate, court ordered adoption or name change, birth certificates of the adopting or legitimating parents, affidavits, etc.). The original FS-240 or replacement FS-240, or a notarized affidavit concerning its whereabouts, also must be included.

Most of the the comments #4 are correct, BUT my wife and I did NOT have to show our marriage license, and we NOT show any physical residence in the USA. I had lived in Mexico for over 1 year, and the address we showed was the Mexico address.