On December 21, 2000, the Legal Immigration and Family Equity (LIFE) Act amended the K nonimmigrant visa category to include the spouse and unmarried children of United States citizens. With this modification, the spouse and children of a United States citizen may be admitted to the United States as K-3, K-4 Visa non-immigrants to complete their process for permanent residence.

1. General Steps
(1). The U.S. citizen must have filed I-130 immigration petition with the USCIS on behalf of his/her alien spouse.
(2). File an I-129F, petition for fiancé(e) visa with the regional service center of US Citizenship
(3). I-129F is approved
(4). The spouse applies for the K-3 visa at the US Consulate within four months
①. If the marriage occurred outside of the United States, the consulate where the marriage took place, OR
②. If the marriage occurred in the United States, the consulate with jurisdiction over the current residence of the alien spouse.
(5). Get K-3 visa and enter into US

2. Basic Requirements
(1). Be the spouse of a United States citizen
(2). Have a pending relative petition, Form I-130 filed with the USCIS
(3). Have the intent to enter the United States in order to await the completion of the permanent residence process
(4). Have an approved Form I-129F, Petition for Alien fiancé(e)

3. Validation
Generally speaking, K-3 visa is valid for two years. The K-3 holder must leave US in 30 days after the termination. But it is no longer valid 30 days after one of the following:
(1). Denial of the I-130
(2). Denial of Adjustment of Status
(3). A final divorce of the marriage
(4). A K-4 nonimmigrant turning 21 years old or marrying
(5). Approval of permanent residence for the K-3, thus terminating the derivative K-4 status

4. Documents
(1). Petitioner
①. Certificate of naturalization, certificate of citizenship, or U.S. birth certificate
②. Passport
③. Documents to prove that all previous marriages were legally terminated (divorce decrees, or certificate of divorce)
④. Legal documents to show how the name change occurred (i.e., a marriage certificate, adoption decree, court order, etc.)
⑤. Tax returns or tax return of other sponsors in past three years, if any.
(2). Beneficiary
①. Passport of your alien spouse
②. If you has been previously married, provide documents to prove that all previous marriages were legally terminated (divorce decrees, or certificate of divorce)
③. If your name shown in the above mentioned documents have changed, provide legal documents to show how the name change occurred (i.e., a marriage certificate, adoption decree, court order, etc.)