OBJECTIVES: To elucidate the importance of mutual effects within dyads by examining the contribution of depression on quality of life (QOL) in patients with advanced cancer and their family caregivers (FCs). SAMPLE & SET TING : 716 patients with advanced cancer paired with their FCs at two large, private not-for-profit hospices. METHODS & VARIABLES: A descriptive, cross-sectional design with the baseline data of a randomized hospice clinical trial was used.