Background: The purposes of this study, performed on a large sample of cancer patient-caregiver dyads, were: i) to simultaneously investigate, using an individualized quality of life (QoL) measure (Schedule for the Evaluation of Individual QoL, SEIQoL), the QoL domains freely expressed by cancer patients and their caregivers, and ii) to explore overlapping between the SEIQoL assessment and QoL assessment using traditional instruments.; Methods: The study employed a cross-sectional design including cancer patients who were going to receive chemotherapy treat