An analysis of changes in sex mortality ratios (the ratio of male to female deaths) between 1979 & 1987 for adults in 23 developed countries is reported in this article. During the 1980s sex mortality ratios continued to increase for 25-34 year olds, but showed mixed trends for other age groups. Additional data on trends are presented & reviewed. It appears that recent trends in ratios have been influenced by changing sex differences in smoking & in a variety of other factors. (61 Refs.)