Nina Cassian was born Renée Annie Katz to a Jewish family in Galati, Romania. Her father was a noted translator of German and English writers, including Edgar Allan Poe. When she was 11 years old, her family settled in Bucharest and she attended schools in the Jewish ghetto there. As a teenager, she joined a Communist youth organization. She trained as a pianist from an early age and studied painting, literature and composition at the University of Bucharest. She took the pen name Nina Cassian and published her first poem in the daily România liberă in 1945, and her first poetry collection in 1947. She went on to become a prominent poet, writer and translator in Romania and also was well known in the West. Her first husband was Vladimir Colin, a poet; they divorced after six years. She remarried to Alexandru Stefanescu, a writer and editor who died in 1984. In 1985, she won a Fulbright fellowship that enabled her to come to New York, where she was a visiting professor of writing at New York University.
During this time, a Romanian friend and opponent of the dictator Ceausescu's government was arrested and tortured to death by the state secret police. Several unpublished poems by Ms. Cassian satirizing the government were found among his papers. She could not return home and was granted asylum in the USA. She contributed poems in English and in translation to The New Yorker, The Atlantic Monthly, and other magazines, and published the collections Life Sentence (1990) and Take My Word for It (1998) In 1998, she married as her third husband Maurice Edwards, former artistic director of the Brooklyn Philharmonic.