The McMaster Quality of Life Scale (MQLS) was developed to measure the quality of life in a palliative patient population. This paper describes the tool and its psychometric properties. Palliative stage patients could assess their condition using this tool (r = 0.84; 95% Cl 0.76-0.94). Although ratings by different raters (patient, family, staff) were correlated, systematic differences were found by source of rating, which suggests that proxy rating (substituting family or staff ratings for a patient rating) should be avoided. The MQLS was sensitive to changes in the patient's quality of life. Neither age nor sex of patient influenced total score obtained. Persons close to death rated their quality of life as being poorer than those who were alive at the end of the data collection period. People who needed to have the MQLS read to them rated their quality of life somewhat lower than patients who could complete the task by themselves. Staff-rated MQLS scores correlated significantly with the staff-rated Spitzer Quality of Life Index. This study suggests the MQLS is a reliable and valid measure of quality of life during the palliative phase.