Neuroimaging studies of reading have so far mainly focused on the description of brain regions involved in processing writ words, particularly through approaches revealing the average activation pattern of entire groups of subjects. The aim of the present study was to contribute to the question of functional inter-individual variability of reading, and investigate whether reading can rely on different brain activation patterns, even in literate subjects, in a way that reflects their level of proficiency with written material. The present fMRI results obtained with a group of 33 literate subjects are consistent with models of reading postulating the existence of two routes to access words. They show that subject's proficiency with written words is one factor that can shape the amount with which subjects rely on one route or the other. An essential functional set of brain regions was found to be reliably activated by each subject of our group, and its implication did not vary as a function of the reader's skill. This set comprises regions devoted to the visual analysis of words (bilateral occipital regions and the left occipito-temporal junction), access to semantics (the basal temporal language area) and pronunciation (left rolandic sulcus) and could correspond to a direct access to words. Lower skilled readers showed a greater involvement of additional regions related to the grapho-phonological conversion of words. The deactivations observed in these regions for the most proficient readers indicate a functional independence of the two routes to access words.