Thissstudy was an attempt to investigate the effect of task based instruction on improving stu~ents' writing skills at Grade .g Hara General Secondary School in North Wollo. This research study was mainly experimental in design. To this end, a quasi-experimental study was conducted over eight weeks in Hara General Secondary School with a control group, an experimental group, a pre-test and a post-test. The purpose of the experiment was to find out the effect of task based instruction on improving students' writing skills. To this effect, an intervention program was conducted to enhance the writing ability of the experimental group started from March up to the end of April in 2008 E.c. Pre-test and post-test measures were analyzed using a t-test statistical procedure. In addition, questionnaire with experimental group was employed in order to measure their perception towards task based language teaching program. The data gathered through '1ifferent instruments were analyzed quantitatively and qualitatively. The main participants of the study were two sections of Grade 9 of Hara general secondary school students. The number of students who involved in the study was 116 from control group and experimental groups but Sixty (60) students from experimental group took part in filling in the questionnaire because the question was meant only for this group. Teaching material which mainly consisted of task based writing was prepared and used during the experiment. Grade 9 English textbooks and inter!Jjtional "ELT resource books were the main sources for the preparation of the teaching material. •he results of the pre-test showed that there was no significant difference in students' writing between the control and experimental groups prior to the experiment. The results of.the post-test showed that there was a significant difference between the control and experimental groups in students' writing abilities (P<0.05). Questionnaire was distributed after the experiment for only the experimental group. The data obtained from the students' questionnaire also indicated that students in the experimental group had a positive attitude towards task based instruction in the context of writing. The data revealed that task based writing helped them improve their writing abilities. On the basis of the findings of the study, it was concluded that task based writing improved students' writing ability. Based on this, conclusions and recommendations were made. .. I