The aim of this study was to examine the effectiveness of a new 9th grade biology curriculum on students' environmental awareness. Participants included 91 ninth grade students in a high school in Balikesir during the spring semester of the 2008-2009 academic years. Two classrooms, including 22 and 24 students respectively, were randomly assigned to a control group, and two classrooms, including 22 and 23 students respectively, were assigned to an experimental group. Three instruments were used in the study: The Environmental Awareness Questionnaire, a semi-structured observation form and a semi-structured interview form. The Environmental Awareness Questionnaire was administered to all students in the study as a pretest and as a posttest. While the experimental group received instructional methods used in the new 9th grade biology curriculum, the control group received traditional instructional methods. Observations were also performed according to a semi-structured observation form and notes were taken during the five-week treatment. After the treatment, 10 students from the experimental group were interviewed using a semi-structured interview form. The data was analyzed using descriptive statistics and independent samples t-test in SPSS 12.0 software. The results of the study revealed that the instructional methods used in the new 9th grade biology curriculum were more effective in increasing the ninth grade students' environmental awareness than compared to traditional instructional methods. (Contains 4 tables.)