Rochelle Paula Walensky (née Bersoff; born April 5, 1969) is an American physician-scientist who is the director of the Centers for Disease Control and Prevention and the administrator of the Agency for Toxic Substances and Disease Registry. Prior to her appointment at the CDC, she was the Chief of the Division of Infectious Diseases at Massachusetts General Hospital and a professor of medicine at Harvard Medical School. Walensky is an expert on HIV/AIDS.