In this study, the effect of conceptual-change-texts-oriented instruction to seventh-grade students' understanding of ecological concepts was investigated. Using information collected through interviews and related literature, the Ecology Concept Test was developed and administered to 58 elementary students in two classes of an elementary school before and after the treatment. The experimental group received conceptual-change-texts-oriented instruction and the control group received traditional instruction. Results of independent "t" test analysis revealed a statistically significant difference between the gain score means of the students in both groups with respect to ecological concepts in favor of experimental group after the treatment.