This article compares the impact of various self-reported chronic conditions on health-related quality of life, as measured by the Health Utilities Index 3 (HUI3), for the population aged 12 or older.The data are from the cross-sectional household component of the Health file of the 1996/97 National Population Health Survey.The effect of 21 chronic conditions was assessed for the full sample (73,402) and in subgroups by age and sex. All analyses were weighted to represent the Canadian population at the time of the survey. The effect of each chronic condition on the HUI3 was estimated using multivariate linear regression, adjusting for age, sex and co-morbidity.The average impact of different chronic conditions on health status varies substantially. At younger ages, urinary incontinence and arthritis/rheumatism have the greatest effect on health-related quality of life, while at older ages, Alzheimer's disease and the effects of stroke have a major impact. Assessments of the impact of any specific condition should account for the presence of other conditions.