Cancer related fatigue (CRF) - a persistent sense of exhaustion related to cancer or cancer treatment - can severely interfere with activities of daily living, and has even been reported to be a factor in patient requests for hastened death. CRF can represent a serious clinical problem years after all treatment has ended. In our research with cancer survivors 1 to 3 years after completion of hematopoietic stem cell transplant (HSCT), 40% of those we interviewed reported that CRF was a major obstacle to the resumption of usual activities. Despite its impact on quality of life, CRF is under-reported, under-diagnosed, and under-treated.