This article focuses on international similarities and differences in levels and trends of mortality for chronic obstructive pulmonary disease (COPD) and asthma in the US, Canada and France from 1969 to 1983. Comparisons have been made of national vital statistics data for age groups 55-64 years, 65-74 years and 75-84 years. From 1969 to 1978, under the 8th revision of the International Classification of Diseases (ICD), the COPD and asthma category included the codes 490-493 and, for the US and Canada, a special code 519.3. From 1979, under the 9th revision, COPD and asthma codes 490-493, 496 were in use in all three countries. The analyses of US, Canadian and French data show lower death rates for COPD and asthma in France. The ratio of male to female deaths from COPD increased with age in the US and Canada, but not in France. The proportion of COPD and asthma deaths attributed to bronchitis was higher in France. An increased use of code 496 (under 9th revision) was observed in the US and above all in Canada. In the three countries, death rates increased faster between 1979 and 1983 in women than in men and increases in women were steeper in the US and Canada than in France. Intercountry comparability is better for COPD mortality in the 9th revision than the 8th revision. Some differences observed between the three countries can be partly explained by coding practices and ICD revisions, but, allowing for differences in coding and classifying respiratory causes of death as well as ICD revisions, death rates are obviously higher in the US and Canada than in France. This suggests that the difference is real.