Abstract-Teaching and learning English as a language of international communication is a vital and important affair.Especially writing in English is one of the most prominent skills in this field. In spite of studying English at different levels, EFL learners are not proficient enough in this basic skill. In a semi experimental design, 28 students were selected from Danesh Gostar Foreign Language center as a sample group. After dividing them into experimental and control group, PET was administered as a pretest, both group were taught writing for 10 sessions of 75 minutes. The experimental group was taught by concept mapping and the other one practiced in traditional instruction model. The students answered the posttest one week after the end of the experiment. The data were analyzed by ANCOVA. The results indicated that the use of concept mapping was efficient in writing achievement for experimental group and. It can be concluded that the use of efficient and practical method like concept mapping as a graphical tool for representation of knowledge that emphasizes on the relationships between concepts, can facilitate and make writing achievement interesting for EFL learners and give depth and meaning to learning.