Background: Transactional models of stress emphasize the role of appraisal of stress in adjustment to illness. The current qualitative study uses this framework to explore the subjective response to these stressors in women with breast cancer. Reappraisals or opportunities for growth from the experience are also examined. Objective: The objective of this study was to explore the experience of stress in Irish women with breast cancer using the Stress-Coping Model. Methods: The diaries of 30 women newly diagnosed with breast cancer were analyzed using thematic template analysis. A template of 5 themes based on elements of the Stress-Coping Model was defined prior to analysis. Results: Six top-level and 14 second-level themes were defined in the final template. Following initial diagnosis of breast cancer, women viewed it as either a threat or a challenge. After diagnosis, however, other stressful events included treatment effects, loss of womanhood, and illness disclosure. Women described coping strategies and social interactions that both increased and decreased their stress. In tandem with negative consequences of breast cancer, women also reported benefit from the experience. Conclusions: Women differed in their identification of stressful events and subsequent coping strategies. Their reports also illustrated the complex relationships between appraisal of the event, personal resources, and social interactions, which can result in both positive and negative outcomes. Implications for Practice: Appraisal of breast cancer can vary, and awareness of this by health professionals can facilitate adjustment. Women need advice in regard to disclosure of diagnosis to others and need more information on managing treatment effects.