The Federal Bureau of Investigation (FBI) and Central Intelligence Agency (CIA) are two agencies in the United States which collect and act upon information that is either related to criminal activity or affects national security. Although the two cooperate in some cases, they have different areas of focus. The FBI is primarily a law enforcement agency, collecting intelligence related to domestic security and performing crime investigation. The CIA is an international intelligence agency which is not responsible for domestic security. The primary difference between the two can be illustrated in their names: the FBI investigates crimes, and the CIA gathers intelligence.

The FBI has a much wider range of responsibilities than the CIA. In addition to addressing some domestic intelligence issues, the FBI also has offices abroad to coordinate information collection. The overseas offices of the FBI alert domestic offices to potential threats and areas of interest. The FBI may determine that action should to be taken to ensure domestic security, and will dispatch field officers as they are needed.

The CIA has a much more extensive network of intelligence gathering equipment and personnel overseas. The primary focus of the CIA is international intelligence, while the National Security Agency (NSA) handles domestic intelligence in coordination with the FBI. In addition, the CIA often cooperates with international intelligence agencies to exchange information. The CIA may pass information regarding domestic security on to the FBI.

The FBI also handles domestic law enforcement issues. The FBI coordinates national efforts to track down missing persons, complex investigations which local law enforcement cannot handle, processing of criminal evidence, and support for victims of crime. FBI agents frequently assist in the collection of evidence in major criminal cases, especially those involving a substantial amount of money or multiple homicide cases.

The CIA does not handle law enforcement. Agents working within the United States are primarily stationed at CIA headquarters in Washington. Domestically based agents interpret information and create intelligence briefings for the President and White House staff. If directed, these agents may supervise overseas agents in carrying out covert actions on behalf of the United States.

The FBI was founded in 1908 during the presidency of Theodore Roosevelt. Initially the FBI was a team of special agents dispatched to investigate unique crimes and support local law enforcement. It was believed that the formation of a division of special agents would reduce corruption and improve the justice system. The FBI investigated violations of federal crimes and assisted other agencies such as the United States Treasury with investigations.

The CIA began life as the Office of Strategic Services in 1942, to coordinate war related intelligence. In 1947, President Truman recognized the continued need for an intelligence agency, and signed the National Security Act to create the CIA. From the beginning, the CIA was designed to be a covert intelligence agency, with much more autonomy over its budget and staff than other Washington agencies.

The FBI as we know it was largely shaped by J. Edgar Hoover, who was appointed as the director of the FBI in 1924. Hoover instituted a series of procedures surrounding promotions, the processing of crimes, and jurisdiction which are still in use today. He also greatly expanded the scope and influence of the FBI in the United States. Hoover also created the beginnings of a national database of criminals and crimes, which has been refined over the years.

Both the FBI and the CIA are vital to American security and information gathering. The organizations work cooperatively in some cases where their interests coincide, but have different agency focuses. Reorganization of both agencies under the 2001 Uniting and Strengthening America by Providing Appropriate Tools Required to Interrupt and Obstruct Terrorism (USA PATRIOT) act has resulted in much more interagency cooperation, and an improvement of the American intelligence community as a whole.