Abstract : The last few decades are characterized by higly increasing mobilities and the central role they play in social and professional integration. The current society requires new capacities of mouvement that deeply modify one's relationship to space and time. However, people cannot equally face these changing and complex new requirements. Observed inequalities of mobility deserve a special attention regarding their involvement in the production and reproduction of socio-economic inequalities. Infering from this statement, this thesis aims at outlining the link between income inequalities and mobilities, integrating different segments of mobility, resolving into socio-demographic groups and underlining the key influence of car access. We concentrate on identifying, measuring and interpretating inequalities of mobility. Simple indicators are used to address the complexity of the phenomenon. A methodical analysis of income impact on daily short-distance and annual long-distance mobility practices and patterns is provided. The assessement is based on the last French National Transport Survey (1993) and Lyons Household Travel Survey (1995). The results obtained show that the income impact varies widely according to the specific segments of mobility analysed. Our approach enlightens different manifestations of socio-economic inequalities on travel patterns. Suggestions are stated here to better take into account the social equity issues in the sustainable management of mobilities.