Joanne Pierce Misko, a former Roman Catholic nun who in 1972 became one of the first two women sworn in as special agents for the F.B.I., breaking the bureau’s longstanding bar against women in frontline law-enforcement roles, died on Friday in Wheatfield, N.Y., east of Niagara Falls. She was 83.

Her brother James Pierce confirmed the death, in a hospital, from a lung infection.

Mrs. Misko had spent 10 years as a member of the religious order the Sisters of Mercy in western New York before deciding to join the Federal Bureau of Investigation as a researcher in 1970, one of the only jobs available to women there at the time.

The bureau’s longtime director, J. Edgar Hoover, had always insisted that only men were physically capable of the arduous and sometimes dangerous work required of special agents. After he died in May 1972, his interim successor, L. Patrick Gray III, opened the role to women.

With her supervisor’s encouragement, Mrs. Misko applied, and within a few months she was being sworn in with 44 others at the F.B.I. headquarters in Washington. She and another woman, Susan Roley Malone, a former Marine, then traveled with the others to the new F.B.I. Academy in Quantico, Va., for 14 weeks of training.

Both Mrs. Misko and Mrs. Malone said they had gotten along well with most of their fellow recruits, with only a few smirks and sideways glances along the way as they mastered the .38 revolver, the two-mile timed run and a host of rules and regulations that every agent has to know.