The aim of this research is to determine the effects of the multimedia applications on the learning achievements of the students when teaching biology. The study is an experimental model. The population of the research is composed of provided by 58 students, from preparatory class of German division of the School of Foreign Languages of Hacettepe University in the spring term of the 2004-2005 academic years. At the beginning of the research, 29 students were chosen randomly for the experiment group and the other 29 students for the control group. The experiment group was taught in an electronic class, with a multimedia CD. On the other hand, without changing the contents of the same subject and by being completely teacher-centered, the experimental group was taught the subject by the same person who had taught the experimental group but by this time in a traditional method by using a blackboard and class notes. In order to collect data of research a 30 multiple-choice achievement test was handed out to both groups at the beginning of the application as a pre-test and again after the application as a post-test. According to the result of the research, it appeared to be that the complete multimedia applications provide higher achievement in reaching to the behaviors at the levels of knowledge, comprehension, and application.