This study is intended to find out whether the Clustering technique gives students better result in writing ability at the second grade of SMPN 1 Baitussalam. The writer used experimental study with pre-test and post-test one group design and the class was taken by using lottery. The result of the test was analyzed by using rating score of writing criteria proposed by Heaton (1988). The instrument of this research was a written test. In addition, the statistical formula are also used to analyze the data. The finding shows that there is a significant improvement on students’ ability in writing after the Clustering technique was implemented. The mean of pre-test was 55.357 and in post-test was 71.71. Furthermore, the result of t-test was higher than t table (t-test=4.859> t-table = 2.16). So, Clustering technique can help the students in writing text from generating until organizing their ideas. The significant level of this research was 0.05. Therefore, it is suggested that clustering technique should be used by English teachers in teaching writing.