BACKGROUND In France 7,720 people were killed in traffic accidents in 2001, 75% of which were men; the number of injured people is estimated at 153,945, of which 65% were men. The objective of the study is to describe differences between males and females regarding accidents, and to explain the main reasons for these differences. METHODS Analysis is conducted from both national police data (2001) and data from the Rhone medical road accident trauma Register (1996-2001). RESULTS The male/female incidence rate is 3.1 for mortality (95% CI: 3.0-3.3) and 1.7 for morbidity (95% CI: 1.7-1.8). Two-wheel motorised vehicle accidents are very specific to males, which explains part of this overrepresentation. The fatality rate and the severe injuries rate among survivors are higher for males. This is true for every main user group (car users, motorised two-wheelers, cyclists, pedestrians) after adjusting for accident circumstances and age of casualties. Males are more severely injured for all body regions and have more often severe after-effects. CONCLUSIONS This paper shows the mechanisms leading to this unfavourable outcome for men. They correspond to differences in the number of trips, in the choice of road transport types, and moreover to differences in risk-taking behaviours. Underlying these behaviours, deep-rooted, strong and rather invariant differences between genders are to be found in the values associated with risk-taking on the road.