This study investigated the effect of conceptual change text-oriented instruction over traditional instruction on students' understanding of cellular respiration concepts and their attitudes toward biology as a school subject. The sample of this study consisted of 84 eleventh-grade students from four classes of a high school. Two of the classes were assigned randomly to the control group, and the other two classes were assigned randomly to the experimental group. During teaching the topic of cellular respiration concepts in biology curriculum, the experimental group was taught with the conceptual change text-oriented instruction whereas the control group was taught with the traditional instruction. The results showed that the students in the experimental group performed better with respect to cellular respiration concepts. In addition, it has been found that there was no significant difference between the attitudes of students in the experimental and control groups toward biology as a school subject. (Contains 2 tables.)