Throughout most of the 20th century the sex gap in life expectancy in theindustrialised countries widened in favour of women. By the early 1980s a reversal in the long-term pattern of this differential occurred in some countries, where it reached a maximum and thereafter has followed a declining trend. It is argued in this study that this development represents an emerging feature of the epidemiological profile of post-industrial societies. I look at Canada and Austria as two representative cases of this phenomenon over roughly three decades, between 1970 and 2001. Decomposition analysis shows that reduced sex differences in life expectancy in the 1980s and 1990s obtained mainly from the effects of reduced sex differences in mortality with respect to heart disease, and secondarily accidents and violence and lung cancer. Heart disease has played a larger role in Canada, whereas differential mortality from accidents and violence has been of greater importance in Austria. A further aspect of the investigation links sex differences in smoking prevalence to sex differences in life expectancy.A model is suggested that incorporates female labour force participation and a measure of gender role traditionalism in society as factors in female smoking prevalence. These variables are also postulated to correlate with change in the sex gap in life expectancy by a time lag of twenty years. It is found that sex differences in smoking prevalence in the past are related to sex difference in life expectancy in the present, and that female labour force participation and gender role traditionalism are also associated with the sex gap in expectation of life. The findings are interpreted in reference to epidemiological transition theory and the literature concerning change in the position of women and sex differences in mortality in high-income nations.