In end-of-life care, rehabilitation for terminally ill cancer patients is inconsistently provided and rarely discussed. We sought to clarify the prevalence of unmet rehabilitation need for patients admitted to inpatient hospice/palliative care units as perceived by bereaved family members. We conducted a nationwide questionnaire survey of 1001 family members of cancer patients who died at inpatient hospices/palliative care units. For cancer patients who did not receive rehabilitation, we asked if family members perceived that the patient would have wanted rehabilitation intervention. Data were obtained from 416 respondents. Of these, 281 (67.5%) cases received no rehabilitation. The need for physical modalities was the most frequently reported (27.8%; 95% CI: 22.6-33.4), followed by relief of dyspnea (25.6%; 95% CI: 20.6-31.1) and treatment of edema (23.8%; 95% CI: 19.0-29.3). A non-negligible proportion of bereaved families reported unmet need for rehabilitation related to symptom management in inpatient hospices/palliative care units.