The Tucson Resident Agency (RA) is the largest RA in Arizona, and is headed by an Assistant Special Agent in Charge. It has investigative responsibility for Pima County, Santa Cruz County, and the Tohono O'odham and Pascua Yaqui Indian Reservations.

FBI Tucson works very closely with other federal, state, and local law enforcement agencies in an effort to combat crime. Task forces that the FBI participates in include:

Innocent Images Task Force - investigating child pornography on the Internet
HIDTA Task Force - joining forces with DEA to combat drug smuggling
Joint Terrorism Task Force - working to stop terrorist threats
Southern Arizona Corruption Task Force - comprised of DEA, ICE, Tucson Police Department, and the U.S. Attorney's Office, with assistance from the Counter Narcotics Alliance in Tucson