This paper aims to increase understanding of how mothers diagnosed with breast cancer while in the paid workforce experience and manage their multiple demands of taking care of themselves, their children and their paid work. In-depth, semi-structured interviews were conducted with 32 women who were mothers of dependent children and in the paid workforce at the time of their breast cancer diagnosis. The sample includes women living in urban and rural Australia. The study found that after a breast cancer diagnosis, participants tended to prioritise their health and wellbeing over paid work. Yet dominance of gendered identity meant that they tended to place the needs of family, especially children, above their own health and wellbeing. The key factors that influenced mothers' decisions to continue in, return to, or leave paid work after a breast cancer diagnosis included: a change in perspective regarding what was important in their lives; level of support from the workplace and home; the extent to which participating in paid work was a financial necessity; the extent to which their identity was connected to paid work, and, ongoing level of pain or fatigue. The paper concludes that using the sociological concepts of the fateful moment, boundary maintenance and a feminist ethic of care produces a more nuanced understanding of women's participation in paid work after breast cancer than examining paid workforce participation, or unpaid responsibilities and mothering, separately. The nature of the permeability or malleability of boundaries between work, family and taking care of the self affects women's participation in paid work during and/or after breast cancer treatment. Increased boundary permeability or malleability brought about more by cooperation than conflict facilitated positive experiences of re-negotiating boundaries, whereas increased permeability or malleability brought about more by conflict than cooperation created difficulties for women in finding an acceptable balance between their family, paid work and taking care of their own health after breast cancer.