Marriage:
If you are a U.S. citizen and wish to marry a Bulgarian citizen in Bulgaria, the Bulgarian authorities require that you make a statement before a U.S. consular officer, swearing that you are legally eligible to marry. The fee for notarization of this statement is $30.
The statement must include the full name of the American citizen (photocopy of U.S. passport) and the full name, date of birth and current address of the Bulgarian citizen spouse. This statement is not required if the American citizen spouse holds dual citizenship and is also a Bulgarian citizen.
The sworn statement must then be taken to the Bulgarian Ministry of Foreign Affairs to be authenticated, before you may get married.
U.S. diplomatic and consular officers are not permitted to perform marriages. Marriages abroad are almost always performed by local civil officials. Marriages in Bulgaria are performed by officials at a civil wedding hall.