The Department of Homeland Security and the Department of Justice are ramping up efforts to investigate U.S. citizens and pursue denaturalization cases. This will result in many U.S. citizens being denaturalized and losing their citizenship. These efforts will have a chilling effect on the number of legal permanent residents applying for U.S. citizenship and will further burden a system that is already delayed in adjudicating and granting immigration benefits. This Practice Advisory reviews the present state of denaturalization and revocation of citizenship. It thoroughly reviews the statutes and caselaw to date in denaturalization and revocation of citizenship. Practitioners handling these cases will find this Practice Advisory to be very useful when defending U.S. citizens who are under the threat of having their citizenship torn away from them.