The aim of this study was to find out the effect of awareness raising of texts with two degrees of complexity (linguistically and cognitively complex vs. linguistically complex and cognitively simple) on Iranian EFL learners' reading comprehension. A factorial design with the use of pretest-treatment-posttest was used. In this regard, 120 students in four intact classes formed the sample of the study from Islamic Azad University- Gilan Branch, Roudbar, Iran. They were randomly assigned to two experimental and two control groups. In one experimental group, awareness raising of linguistically and cognitively complex texts was conducted, and in the other awareness raising of linguistically complex and cognitively simple texts was manipulated. In the control groups, the same texts were employed without textual awareness raising. The results of Two-way MANOVA revealed the significant main effect of textual awareness raising on both types of texts. The results also showed a significant interaction effect of teaching method and text complexity. It means the effect of textual awareness raising was high when the text was linguistically and cognitively complex and it was low when the text was linguistically complex and cognitively simple. The results can be useful for teachers, students, syllabus designers, and coursebook writers.