The purposes of this study were to examine (a) the relationship between patients' own reports of the highest grade completed in school and their actual reading level and (b) the relationship between literacy and the level of knowledge about self-care after patients had received education involving written discharge instructions. In addition, the content of the materials was analyzed for its cultural sensitivity. Twenty-six patients who had had either hip- or knee-replacement surgery at an inner-city hospital participated in this correlational descriptive study. There was a significant negative relationship between patients' own reports of highest grade completed in school and their actual reading level (r = -.39, p < .05). Rehabilitation nurses should find this study beneficial for developing, assessing, and using written patient education materials appropriate for the reading level of their patient populations.