In the aftermath of the terrorist attacks of September 11, 2001, the FBI transformed itself to enhance its ability to predict and prevent future terrorist attacks. The new comprehensive counterterrorism plan consists of seven basic components: prioritization, mobilization, centralization, intelligence integration, coordination, information technology, and administrative reform. In 1998, the FBI implemented a 5-year plan of investigative priorities; on September 11, 2001, the top FBI priority became the prevention of further terrorist attacks. In order, the FBI’s priorities are: (1) protect the United States from terrorist attack; (2) protect the United States against foreign intelligence operations and espionage; (3) protect the United States against cyber-based attacks and high-technology crimes; (4) combat public corruption at all levels; (5) protect civil rights; (6) combat transnational and national criminal organizations and enterprises; (7) combat major white-collar crime; (8) combat significant violent crime; (9) support Federal, State, municipal, and international partners; and (10) upgrade technology to successfully perform the FBI’s mission. The second component of the FBI’s counterterrorism plan involves the mobilization of hundreds of Special Agents assigned to terrorism matters, intelligence analysis, and translation. Additionally, operational units have been established that provide new or improved capabilities to address the terrorist threat. The third component of the plan involves the centralization of management in the Counterterrorism Program to ensure consistency of priorities and strategies. Counterterrorism operations in the United States and abroad have been integrated to improve coordination with other agencies and governments. The fourth component of the plan involves the development of an enterprise-wide intelligence program to strategically direct intelligence collection, analysis, and dissemination. The fifth component of the plan involves enhancing the coordination and information sharing with State and municipal law enforcement agencies. Substantially upgrading information technology capabilities is the sixth component of the plan and will result in an improved ability to collect and analyze information. The final component of the plan involves bureaucratic reform. The final section offers an assessment of the effectiveness of the FBI’s counterterrorism plan, including case examples. Overall, the FBI’s effectiveness has been greatly enhanced by the implementation of the counterterrorism plan. Figures, tables