This study evaluated the effectiveness of an intervention for second graders at risk for academic failure, which taught reading comprehension embedded in social studies content. The intervention included instruction about the structure of cause/effect expository text, emphasizing clue words, generic questions, graphic organizers, and close analysis of well-structured examples of cause/effect text. It was compared to a program that focused on the same social studies content but without cause/effect training, and to a no-instruction control. Fourteen teachers, randomly assigned to treatment, provided the instruction; 197 7- and 8-year-olds participated. The intervention group demonstrated higher performance than the other groups on both sentence combining and answering comprehension questions. The 2 instructed groups did not differ on the social studies measures, and both were better than the no-instruction group; thus, embedding text structure instruction did not lessen the amount of social studies content acquired. These findings corroborated studies on another text structure (comparison) and extended previous work focused on cause/effect. New findings included, first, more robust group differences in performance than were found in an earlier cause-effect study because of a more precise identification of the instructional level appropriate for this population: the sentence, not the paragraph. Second, examining the sustainability of the intervention effects, a delayed posttest showed that after summer break, the intervention group performed better than the other groups on sentence combining, although not on answering a comprehension question.