Ossining, N.Y., June 30, 2026 ── Sister Mary Ann Duffy, M.M., a Maryknoll Sister of 78 years known for her intellect, curiosity and wit, died on June 5, 2026. She was 95.
Sr. Mary was born on November 11, 1930, to James and Mary Brennan Duffy in Philadelphia, Pa. She is predeceased by four of her siblings, and survived by her sister, Cass Begley.
In 1948, Sr. Mary graduated from West Philadelphia Catholic Girls High School. In September of that year, she entered the Maryknoll Congregation at the Maryknoll Sister Center in Ossining, N.Y. Sr. Mary pronounced first vows on March 7,1951, and final vows on the same date in 1954. She would go on to complete her bachelor’s degree in education at the Maryknoll Teachers College in 1956 and a Master of Arts in Spanish literature at Temple University in 1968.
Sr. Mary was called to Merida, Mexico, for her first mission in 1956. She taught there until 1968, when she was transferred to Puebla, Mexico. During her time in Mexico, Sr. Mary mastered the Indian dialect of the Tzeltal people and developed an experimental system of basic education for them, while providing pastoral care. She served in rural community development across Mexico, as well.
In 1985, Sr. Mary joined Sr. Judy Noone to serve the Maya Quiche people, whose lives had been devastated by military violence. Together, they worked with widows to build community vegetable gardens and contribute to reforestation efforts.
After completing a master’s degree in pastoral studies from Loyola University in 1995, Sr. Mary was assigned to Nicaragua, where she served for two years before working in Mission Promotion. A believer in justice and peace, Sr. Mary then began Congressional Service as a social concerns coordinator.
In her next assignment, Sr. Mary worked as a pastoral agent in Central Guatemala’s San Juan Sacatepequez and Ciudad Queztal, before moving to Centro Pastoral Red DeVida of Darien, Panama, from 2012 until 2016.
Sr. Mary returned to the Maryknoll Sisters Center in 2016, where she was a valued member in service to her Sister community until her passing.
The Maryknoll Sisters would like to thank Sr. Mary for her years of dedicated service to our One Earth Community.
A wake for Sr. Mary was held on June 10, 2026, in the Annunciation Chapel of the Maryknoll Sisters Center in Ossining, N.Y. A Mass of Resurrection was said for Sr. Mary on June 11, 2026, also in the Annunciation Chapel.










