The present study was designed to shed light on whether some of the problems that average and below average readers have in comprehending expository texts stem primarily from lack of familiarity with conjunctions or a tendency to ignore these markers. On the basis of Gates-MacGinitie reading comprehension scores, 93 students in grades 5 and 7 were classified into high, medium, and low reading levels. All students read short expository texts under four conjunction manipulation conditions and answered comprehension questions. The conjunction manipulations within the texts were designed for examination of the roles of analyzed linguistic knowledge and cognitive control in comprehension. Analyses indicated that all groups benefited from the highlighting of explicit conjunctions. The comprehension of interpropositional relationships by average and below average readers was enhanced when explicit conjunctions were available, relative to an implicit condition. Furthermore, the deep processing manipulation (conjunction multiple-choice cloze) actually hindered, rather than facilitated, comprehension for all students. Data on appropriate selection of conjunctions in this condition revealed less knowledge of these important cohesive indicators among average and below average readers than above average readers. Together with the comprehension findings, we conclude that average and below average readers exhibit problems with both knowledge of conjunctions and control over their use in comprehending expository text.