Caltech Employees Federal Credit Union serves an exclusive field of membership-the California Institute of Technology community, family and its affiliate organizations. Employees and members of the following groups are eligible to join CEFCU:
- Employees of the California Institute of Technology who work at the Campus, Jet Propulsion Laboratory (JPL), Mt. Wilson, Mt. Palomar
- NASA employees at JPL
- The Huntington Library, Art Collections, and Botanical Gardens
- Independent contractors and documented volunteers who work regularly for a sponsor facility
- Registered graduate and undergraduate students of Caltech
- Members of the Caltech Alumni Association
- Employees of the Carnegie Institute of Washington located in Pasadena and Palomar
- Employees of California Association for Research in Astronomy (CARA)
- Employees of Thirty Meter Telescope (TMT)
- The Associates of the California Institute of Technology
- Faculty, administration and students of the Polytechnic School
- Faculty, administration and students of the Child Educational Center (CEC)
- Immediate family of current members
Once membership has been established a member may retain their account for as long as they desire, even if they leave their qualifying sponsor organization. This principle known as "Once a member, always a member" is in full effect at Caltech Employees Federal Credit Union.
Immediate family of a current member includes their husband, wife, children, grandchildren, parents, grandparents, brothers and sisters (by blood or marriage) or any extended family or any one adult who the primary member deems a significant other living within the same household as the qualifying member.
In addition, CEFCU also provides membership for members retired from active employment with the above groups, unremarried spouses of deceased members, and Caltech and JPL-based clubs and organizations.