The present research aimed to determine the circumstances under which comprehension between paper and e-readers is comparable and what role working memory plays in successful comprehension of text presented in these formats. Narrative and expository texts were presented in electronic and paper formats to determine whether readers glean different information for these text types via different presentation formats. Results indicated that comprehension for paper and electronic formats may not be equivalent. Although comprehension of thematic information presented via e-reader was better than when reading for detail (as in expository passages), it did not lead to comprehension as successfully as printed text. In addition, removing working memory led to the disappearance of the effects of presentation method and the type of questions, suggesting that it was important for individual differences in use of the e-reader device. Implications for the appropriate use of e-readers are discussed.