The abstention rate in French elections has been rising steadily for the past twenty years. While many commentators have inveighed against this self-disenfranchisement and the crisis it is causing in representative democracy, another group that has shunned civic commitment in a much more fundamental way - the non-registered voters - has not elicited such criticisms. One singular feature of the French electoral system is that citizens who wish to vote must actively register their eligibility on an electoral register. There is no penalty for failure to do so as there is in Belgium or Greece (Boy and Mayer, 1997a). The voting qualifications are: being I 8 years of age, a French national - nationals of other European Union countries can register on supplementary lists for local elections and elections to the European Parliament-, not being under a legal disability, and proving a firm connection with the municipality of registration (i.e. either having one's legal address or at least six months' continuous and effective residence there, or having paid the land tax. community charge, or business use tax there for at least five years previously). Since 2001, however, town halls have had a duty to automatically register young people who will be aged 18 at the time of an election. Registration must be carried out before the year of the election, and is then permanent but subject to revision. Registers are. at least in theory, updated annually. Electors who change address, including within the same municipality, must be removed from the register if they fail to re-register at their new address. The non-registered population thus consists of eligible voters who have not registered, as well as voters removed from the register for reasons other than legal disability and who have not re-registered. In all. non-registration results from the following circumstances: accidental or intentional failure to register, and. congruently. accidental or intentional failure to re-register. Non-registrants can, therefore, be presumed to form a heterogeneous group.Non-registrants are often classed with abstentionists because of their common failure to participate in elections, but they differ in several respects. The first part of this study reviews the differences between nonregistration and abstention. It then goes on to consider the explanatory factors of non-registration using data from the 2001 Neighbourhood Life Survey (Enquete Vie de Quartier). With this survey, individual characteristics, not usually available simultaneously, can be compared in a single model that evaluates the specific ceteris paribus effects of each on nonregistration. This ad hoc survey, included as part of the continuous surveys on household living conditions (EPCV) established by INSEE, set out to study individual disparities in the various socio-economic categories of neighbourhood(1). To facilitate comparison at the extremes, the residents of high-income and low-income neighbourhoods were over-represented in the sample. Data collection took place between April and June 2001 on a sample of 11,919 people.Beyond the influence of individual characteristics, it is legitimate to wonder whether the concentration of disadvantaged groups in one place creates an specific to the neighbourhood which would increase non-registration. The premise here is that a sense of being second-class citizens makes residents of poor neighbourhoods indifferent to political discussions they see as irrelevant to their problems, and leads them to disengage from electoral life. The existence of a potential socially disadvantaged neighbourhood effect on electoral registration will be tested for in the third section, using individual-level data from the Neighbourhood Life Survey.I. Non-registration is different to abstentionBoth abstention and non-registration concern groups who are younger and lower-income than the voting-age population as a whole (see in particular, Gaxie, 1978; Morin, 1983; Percheron et al. …