There had been many studies conducted to investigate the benefits of Mind Mapping (MM) in the writing process and Three-Step-Interview (TSI ) in the speaking process, this study set out to investigate the effectiveness of an integrated technique which was the combination of MM and TSI in teaching writing. This technique was intended to facilitate the students with individual and group brainstorming practice and to help create another teaching procedure which could effectively solve the students’ writing problem, especially in generating and organizing ideas in the pre-writing process. The subject of this study was 29 students who took Intermediate Writing subject at English Department Faculty of Education, Lampung University-Indonesia . The pretest and posttest were administered before and after the treatment. The data was analyzed by means of the paired sample t-test. The result shows that the students' writing ability significantly improved subsequent to the treatment. It also reveals that the most significant improvements were those of the writing content and organization aspects. The results are discussed in relation to relevant previous research findings.