The purpose of this research was to examine the effects of two different methods of teaching physics (Case-based Learning and Traditional Instruction) on the conceptual understanding of 9th-grade students regarding topics related to energy. The research was conducted in two different 9th-grade classes in a high school. The research used a pretest/post test quasi-experimental method with a nonequivalent control group. The research was carried out with two groups--a study group (n = 30) and a control group (n = 30). The Study group were instructed using the method of Case-Based Learning while the control group were approached with traditional teaching methods. Data for the research were collected using the "Energy Conceptual Test." The data collected were analyzed in the SPSS 15.0 statistics program in terms of frequency, percentages, arithmetic means, and standard deviation. When the results of the study were examined as to the changes in the conceptual understanding attained in the two groups (on a question basis), it was found that the most positive change could be seen in the case story group.