Civil Service Retirement System (CSRS) Under CSRS, Federal Employees will be entitled to a basic annuity. Generally, the accumulation of this annuity benefit will be quite larger than that of the basic annuity within the FERS system.
Federal Employee Retirement System (FERS) FERS became effective on January 1, 1987. It replaced CSRS, which had more of a defined-benefit pension structure in its benefits framework.