The largest DNA database is the The National DNA Index System (NDIS), created by the FBI (USA) in 1994 and which, as of April 2010, contained 8,201,707 offender profiles and 315,789 forensic profiles.

National DNA Index System (NDIS) is a system of DNA profile records input by criminal justice agencies (including state and local law enforcement agencies) and stores profiles of people convicted of serious violent crimes, such as rape and murder, but the system has been expanded repeatedly, first to include all convicted felons, then misdemeanants and state arrestees.
USA – FBI website http: //www.fbi.gov/hq/lab/codis/clickmap.htm
UK – National Policing Improvement Agency (NPIA): www.npia.police.uk/en/14189.htm