Since 9/11, a concern has been that terrorists or their supporters would seek to immigrate to the U.S. (i.e., seek lawful permanent residency (LPR)). The U.S. Citizenship and Immigration Services (USCIS) conducts background checks for those applying for LPR. This report reviews USCIS's processes for screening individuals applying for LPR. The auditor assessed: what data show about the extent to which national security concerns were discovered during USCIS background checks for LPR applications; what issues USCIS has encountered in its background check processes and what actions have been taken to resolve those issues; and the extent to which USCIS has addressed fraud vulnerabilities in its adjudication procedures for LPR. Illus.