More than 200,000 federal workers could retire early during a special 60-day period this year under a bill introduced by Sen. William V. Roth Jr. (R-Del.).

Roth's plan, which has been blocked in the past by congressional Democrats and some federal unions, would temporarily waive age and service requirements. Most employees can't retire on immediate pension until they are age 55 with 30 years of service; age 60 with 20 years', or age 62 with five years' service.

Under the Roth plan, employees could retire at any age with 25 years of service, at age 50 with 20 years', at age 55 with 15 years' or at age 57 with 5 years of service. The early-out would not be offered to some law enforcement agents, air traffic controllers, members of Congress or federal judges. The president would be able to designate other groups of workers who could not take early retirement.

Although employees like to have the early-out option, relatively few take it when given the chance. About one in every six employees given an early-out offer actually retires then. Those numbers are based on early-outs limited to specific agencies or localities. There has never been a government-wide early-out offer.

Benefits for people taking the early-out would be reduced 2 percent for each year they were under age 55.

Roth says some of the salary money saved by the early-outs could be plowed back into federal pay raises.

Federal unions, which could lose a lot of members in an early-out, object to the Roth bill because they contend it would weaken critical services to the public and allow private contractors to take over jobs now performed by civil servants.

Meanwhile, Rep. Barbara Boxer (D-Calif.) plans to reintroduce her bill that would authorize an early-out for Defense Department civilian employees. Her plan would allow employees to add five years to their age or service time to qualify for retirement. Anyone already eligible could still get an extra five years' credit under her plan. That would boost their pensions at least 10 percent.

Boxer picked up a respectable number of co-sponsors last year when the Defense Department was cutting employment. Obviously, Defense isn't going to cut jobs during the Persian Gulf War, but experts anticipate cutbacks once the situation is settled. Job Mart

The National Transportation Safety Board is looking for a Grade 9 through 11 editor ($25,717 to $31,116 to start). Call 202-382-6523. Diplomatic Security Jobs

The State Department plans a job fair Saturday at its Dunn Loring training site. State wants Foreign Service diplomatic security officers and special agents, $23,756 to $28,366. For details, call 202-663-0056. Federal Personnel Guide

The 1991 issue of the federal-postal worker/retiree fact book is out. In addition to pay and leave charts, it has an updated section on the federal employees' tax-deferred thrift savings plan. Single copies are $7. You can write the Federal Personnel Guide at P.O. Box 42578, Washington, D.C. 20015-0578 or call 301-656-0450.