The quality of life of caregivers of patients with cancer is an important construct given the substantial impact of caring on the physical, psychological, social, and financial well-being of caregivers. Moreover, caring for patients with cancer also affects family functioning and places burdens on caregivers. The reliability and validity of instruments used to assess the quality of life of caregivers of patients with cancer were reviewed to aid in the selection of the most appropriate measures for research and practice. (1980-2000) and (1982-2000) searches located relevant quality of life instruments using the keywords "cancer and quality of life" and "caregiver or spouse or partner." The search identified the following instruments: the Caregiver Quality of Life Index-Cancer Scale, the Caregiver Quality of Life Index, the Quality of Life Tool, and the Quality of Life Index-Cancer Version. Quality of life instruments developed specifically to measure the quality of life of caregivers of patients with cancer had the best psychometric properties. The Caregiver Quality of Life Index-Cancer Scale, in particular, met or exceeded minimum psychometric criteria for reliability and validity. The development of reliable and valid caregiver quality of life measures is an important factor in developing interventions to enhance quality of life of caregivers of patients with cancer.