Evaluation of mobile mammography for reducing social and geographic inequalities in breast cancer screening participation. We examined the responses to first invitations to undergo breast cancer screening from 2003 to 2012 in Orne, a French department. Half of the participants could choose between screening in a radiologist's office or a mobile mammography (MM) unit. We calculated the participation rate and individual participation model according to age group, deprivation quintile and distance. Among participants receiving an MM invitation, the preference was for MM. This was especially the case in the age group >70years and increased with deprivation quintile and remoteness. There were no significant participation trends with regard to deprivation or remoteness. In the general population, the influence of deprivation and remoteness was markedly diminished. After adjustment, MM invitation was associated with a significant increase in individual participation (odds ratio=2.9). MM can target underserved and remote communities, allowing greater participation and decreasing social and geographic inequalities in the general population. Proportionate universalism is an effective principle for public health policy in reducing health inequalities.