Immigrants who are alleged to be involved with gangs are top immigration enforcement priorities for the Department of Homeland Security (DHS). This is true even if they have no criminal convictions and DHS is targeting them based on allegations alone. If such individuals choose to apply for immigration benefits, they may be exposing themselves to serious risk. This practice advisory discusses what gangs and gang databases are, how allegations of gang membership arise in immigration cases, the over-inclusive process law enforcement employs to allege gang membership, and strategies to identify whether your client may be labeled a gang member or associate. The purpose of this advisory is to help immigration advocates better understand how law enforcement in the United States documents and alleges gang membership or association, such that advocates are able to identify red flags in cases, and are better prepared to work with clients to assess possible risks in filing for relief.