Daughters caring for a mother with breast cancer represent a vulnerable population. They are confronted with having to integrate their emotional reactions to their mother's illness while simultaneously processing concerns about their own personal susceptibility. Through their caregiving, daughters obtain intimate knowledge of their mother's breast cancer experience. As part of a study of breast cancer survivorship and the family, in-depth interviews were conducted with a diverse sample of adult daughters caring for their mother with breast cancer. Analysis of the daughters' narratives documents that their mother's cancer diagnosis subjects them to a period of crisis fraught with severe emotional distress and life and death concerns that parallels the ‘existential plight’ that patients encounter following the cancer diagnosis and inception of treatment. Specifically, the daughters' accounts demonstrate that the diagnosis intensified their bond with their ill mother, while also presenting challenges in their relationship. It precipitated a re-definition of personal values and altered their perceived future. Their mother's illness prompted recognition of increased family risk and rendered daughters with a heightened sense of personal vulnerability. Clinicians need to appreciate the extent to which daughters can be impacted by their mother's cancer experience. Copyright © 2004 John Wiley & Sons, Ltd.