The main purpose of this study has been to compare the concept mapping with the traditional instruction method in consideration of student's achievements in English course. The students who took "English" class in 9th grade at Balakgazi High School in 2005-2006 attended this study. An experimental group and a control group consisting of 23 members each, were organized. The concept mapping was carried out to the experimental group. Traditional instructional method was carried out to the control group. Various concept maps related to these subjects were developed. An achievement test was used to collect the data and then a Questionnaire was developed to determine the students' views about the concept mapping. The primary findings indicate that: (1) Comparing the control group the experimental group that the concept mapping was carried out has become more successful; (2) In permanent of knowledge there has been no significant difference between groups; and (3) The students have had some difficulties while developing concept maps on their own. According to the results of this study, it may be recommended that: (1) While using concept maps in language teaching, teacher-made maps firstly should be used; and (2) The students should be encouraged to develop their own concept maps. (Contains 5 tables.)