Summary:This prospective longitudinal study examined both shortand long-term changes in health-related quality of life (HRQL) in 52 breast cancer patients with poor prognosis receiving high-dose chemotherapy (HDC) treatment with autologous blood stem cell transplantation (ASCT). HRQL was measured seven times from baseline to 2 years post enrollment with the Functional Living IndexCancer (FLIC), the EuroQol (EQ-5D), and a quality of life visual analogue scale. The percentage of questionnaires returned at each assessment time ranged from 80 to 92%. All three measures showed a similar pattern of change, with HRQL decreasing following administration of HDC, and returning to baseline levels 8 weeks post HDC. A repeated-measures analysis of variance showed that the FLIC at 2 years was significantly better than baseline (P ¼ o0.0001). Difficulty sleeping, headaches, and decreased sexual interest were the most common symptoms reported in the longer term. Our results have implications for early psychosocial intervention in the care of breast cancer patients with poor prognosis undergoing treatment with HDC and ASCT because such interventions can further improve the quality of their survival.