The Civil Service Retirement System (CSRS) originated in 1920 and has provided retirement, disability and survivor benefits for most civilian employees in the Federal Government. The CSRS has traditionally been a single benefit retirement plan. Employees have had one payroll deduction for the plan and, after retirement; have received one check from CSRS each month for the rest of their lives.
CSRS employees may also contribute to the Thrift Savings Plan in order to receive additional retirement income. If you stay with CSRS, you can contribute up to 5% of your basic pay each pay period and receive a tax break today. (CSRS, including CSRS Offset employees, receive no agency contributions to their Thrift accounts.)
For more information visit https://www.opm.gov/retirement-services/csrs-information/.