The transition from curative to palliative care for elderly patients with cancer-related asthenia presents complex challenges to oncologists. A result of this complexity is a lack of regard for the maintenance of physical and mental function. This study examined the effects of comprehensive, multidisciplinary, inpatient rehabilitation on the physical and mental function of elderly cancer patients with asthenia. We found that both physical and mental function improved following inpatient rehabilitation. However, it is difficult to predict which patients benefit most from rehabilitation. Nevertheless, functional improvement following rehabilitation may allow medical caregivers to better distribute the type and intensity of care, and reduce the caregiver burden experienced by family members in the home.