This study examined the effects of instruction focusing on text structures on EFL students' comprehension for expository prose. Two classes of twelfth grade students in a Korean high school participated in this study. One of the classes was assigned to the experimental condition, in which a reading strategy based on text structure was taught, and the other to the control condition, in which a conventional reading lesson was given. To assess the instructional effect a pretest-posttest design was employed. The results of this study indicated that teaching text structures markedly improved the Korean students' reading comprehension of expository texts.