The aim of this study is to explore the effect of the learning environment, equipped with activities prepared according to the Brain-Based Learning Theory, on academic achievements and biology course attitudes of ninth grade students, compared to the conventional learning environment. The research was carried out using the experimental research model with pretest-posttest control groups. The research was conducted with 44 students placed in experiment and control groups and selected from the ninth grade students of a high school during the 2007-2008 academic year in Ankara through the objective appointment method. The data gathering tools of the study were; the personal information questionnaire, the substance transportation in cell achievement test, and the attitude scale. The data gathered through these tools were analyzed through the SPSS software. After the analysis, it was determined that teaching the subject of substance transportation in cell with brain-based learning activities increases student achievement. In addition, it was concluded that the brain-based teaching does not create any difference in students' attitudes towards the biology course.