Background: In Switzerland, women live about six years more than men. The purpose of our study was to measure and describe the respective contributions of the various age groups and causes of death to the difference in life expectancy at birth between men and women. Methods: With an analytical demographic method, this difference in lift expectancy can be distributed according to age and cause of death. The contribution of each age and cause can be discussed. Results: All ages and quite all causes of death contribute to overmortality in men. Age groups over 50, as well as circulatory diseases and malignant neoplams, contribute most to gender disparities in longevity while violent deaths play a less important role. Conclusions: Any attempt to reduce gender mortality disparities would involve the modification of a number of etiological factors, including biological factors or those linked to lifestyle.