Previous work has demonstrated that illiterate individuals exhibit reduced performance on measures of working memory, relative to a literate cohort. Given the relationship of working memory to phonological processing, which is enhanced by literacy, we sought to examine working memory in illiterate individuals and whether differences can be attributed to artifacts of the test typically used. To the extent that differences actually exist, we also examined whether they can be attributed to the effects of literacy per se or whether they reflect the effects of formal schooling. To accomplish this, we explored the performance of four groups of participants (illiterate, functionally illiterate, self-educated literate, school-educated literate), on five tests of working memory. Illiterate groups performed more poorly than the literate groups on all measures except the "Spatial Span" forward condition and "Remembering a New Route." Our results suggest that differences in working memory performance among literate and illiterate individuals can be attributed to literacy per se. Formal schooling, however, appears to enhance working memory skills. Finally, we stress the need to use tools that are not influenced by literacy and schooling effects in the clinical assessment of illiterate individuals.