This paper is the first to examine the Reading and Writing Self-Efficacy Scale among incarcerated adults. The aim was to examine whether performance of reading and spelling tests (Reading Speed, Nonsense Words and Spelling) explained individual differences in the participants' efficacy beliefs in reading and writing. Six hundred subjects rated their efficacy beliefs in reading and writing, and 92 of them were also sampled for a reading and spelling test. Factor analysis yielded a two-factor solution dividing the reading items and writing items into separate factors and hierarchical regression analysis revealed that education level and test performance accounted for 36.9% and 34.9% of the statistical variance in reading self-efficacy and writing self-efficacy, respectively. The results suggest that assessment of self-efficacy in reading and writing should be included in a screening procedure of reading and spelling difficulties. (Contains 5 tables.)