This study describes the concordance between advanced cancer patients' self-report of quality of life and their caregivers' perception of the patients' quality of life at two time points. It is often necessary for health professionals to rely on information about the patients' quality of life that is provided by family caregivers (proxy), even though information from the patients is considered ‘the gold standard’. Therefore, it is important to establish how reliable this proxy information is. Data were collected 4–6 weeks following diagnosis of recurrent or progressive disease, and again 12 weeks later. Fifty-one patients and their caregivers completed the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30), version 2.0 at both time points. Descriptive statistics were used to calculate patient and caregiver scores and describe the sample. The level of agreement between the two scores, the patients' self-report and the family caregivers' score, was calculated on the mean scores of each scale. In general, most caregivers were able to accurately rate the global quality of life, the level of functioning and the degree of symptom distress experienced by the person they were caring for, when compared with the patients' self-rating. Caregiver ratings for physical domains tended to be more in agreement with those of patients as compared with ratings of the psychosocial domains. This study suggests information from proxy raters is reliable when the proxy is a family caregiver, and this remains true over time.