Eligibility is based on your age and the number of years of creditable service and any other special requirements. In addition, you must have served in a position subject to CSRS coverage for one of the last two years before your retirement. If you meet one of the following sets of requirements, you may be eligible for an immediate retirement benefit. An immediate annuity is one that begins within 30 days after your separation. There are five categories of benefits under the Civil Service Retirement System:

• Optional: If you leave Federal Service after you meet the age and service requirements, you are eligible for an optional annuity. If you leave Federal service before you meet the age and service requirements for an immediate retirement benefit, you may be eligible for deferred retirement benefits. To be eligible, you must have at least five years of creditable civilian service and be age 62.
• Special Optional: You must retire under special provisions for air traffic controllers or law enforcement and firefighter personnel. Air traffic controllers can also retire at any age with 25 years of service as an air traffic controller.
• Early Optional: Your agency must be undergoing a major reorganization, reduction-in-force, or transfer of function determined by the Office of Personnel Management. Your annuity is reduced if you are under age 55.
• Discontinued Service: Your separation is involuntary and not a removal for misconduct or delinquency.
• Disability: You must be disabled for useful and efficient service in your current position and any other vacant position at the same grade or pay level within your commuting area and current agency for which you are qualified. The disability must have onset prior to retirement and should be expected to last for at least one year.