- Abstract Background: While caring for critically ill and terminal patients can elicit grief symptoms in health care professionals, few studies have examined oncologists' grief over patient loss using a qualitative approach to inquiry. Objectives: To explore what makes patient loss difficult for oncologists and to explore the context in which these losses were occurring. Method: Twenty oncologists were interviewed at three oncology centers in Canada about their experiences of grief over patient loss. Exclusion criteria included never having lost a patient in their care and being unable to speak English. Data was analyzed using the grounded theory method. Results: Oncologists found patient loss particularly difficult for relational reasons including instances where they felt close to patients and their families, when they had a transference to the patient, when patients died young, when they had long-term patients, and when deaths were unexpected. Contextual reasons included when patients and their families were unprepared for death, had unrealistic expectations about cure, when excessive treatments were perceived to be used, when physicians were blamed for the loss, or when families were chaotic or had high needs. Findings further revealed that these losses were occurring within a physician culture that had a stigma around death and dying, viewed emotion as weakness, was focused on cure, and was gendered. Conclusions: Effective interventions to help oncologists cope with grief must identify the expectation gaps between physicians and patients when it comes to end-of-life care.