Rosalie Bertell was born to Paul G. and Helen (née Twohey) Bertell in Buffalo, New York. Her mother was Canadian, her father a citizen of the USA. In 1966, she received a Ph.D in Biometrics from the Catholic University of America. From 1969–1978, Sister Dr. Bertell was senior cancer research scientist at Roswell Park Cancer Institute. She was a consultant to the US Nuclear Regulatory Commission, the US Environmental Protection Agency, and to Health Canada.
In 1983, she received the “Hans-Adalbert Schweigart”-Medal from the World Union for Protection of Life. She was president of International Institute of Concern for Public Health from 1987 to 2004. She founded the International Medical Commission Chernobyl in 1996 and is also member of the International Medical Commission on Bhopal since 1994. Bertell was also a vocal advocate against chemtrails.