- For DEFCON used in the military sense, see Defense Condition.
DEF CON is the world's largest annual hacker convention, held every year in Las Vegas, Nevada. The first DEF CON took place in July, 1993. DEF CON is renowned for the "arcane arts" of drinking, socializing, debugging, and crowd control.
DEF CON now has started monthly meetings in local areas worldwide known as DEF CON Groups or DC Groups.
Many of the attendees at DEF CONs include computer security professionals, "crackers" (i.e., malicious hackers), and hackers with a general interest in computer code and computer architecture.