This is the first report on the McGill Quality of Life Questionnaire (MQOL), a questionnaire relevant to all phases of the disease trajectory for people with a life-threatening illness. This questionnaire differs from most others in three ways: the existential domain is measured; the physical domain is important but not predominant; positive contributions to quality of life are measured. This study was conducted in a palliative care setting. Principal components analysis suggests four subscales: physical symptoms, psychological symptoms, outlook on life, and meaningful existence. Construct validity of the subscales is demonstrated through the pattern of correlations with the items from the Spitzer Quality of Life Index. The importance of measuring the existential domain is highlighted by the finding that, of all the MQOL subscales and Spitzer items, only the meaningful existence subscale correlated significantly with a single item scale rating overall quality of life.