We analysed word reading and spelling in French adults with low levels of literacy (A-IL). As well as examining phonological and lexical processes, we explored the relationship between literacy and oral language skills. Fifty-two adult literacy students were compared with reading level-matched pupils in Years 1-3 of primary school on reading tasks (pseudoword reading, word reading, text comprehension), spelling tasks (pseudoword spelling, text dictation) and oral language tasks. A-IL scored the same as children on word reading and spelling but less well on pseudoword reading and spelling. They also produced fewer phonologically acceptable errors in the dictation. Regarding oral language skills, as a group A-IL encountered greater difficulty in phonology than in morphosyntax and semantics, and correlations revealed strong relationships between literacy levels and oral skills, particularly in the domain of phonology. Within their group, however, A-IL displayed several distinct language profiles. These could reflect different risk factors leading to functional illiteracy and are discussed regarding the cognitive and environmental causes of impaired reading acquisition.