The present study investigated differential effect of two types of feedback namely, computer-mediated and metalinguistic, on Iranian EFL learners’ writing accuracy. To this end, based on Nelson Proficiency Test (300 A), 69 Iranian advanced EFL learners, including 45 males and 24 females, aged between 17 and 24, learning English in language institutes in Salmas, were selected randomly out of the total population of 121 EFL learners and then divided into three groups. The participants in the two experimental groups received metalinguistic and computer-mediated feedback separately while those in the control group received no feedback. The analyses of the results obtained through a pre-test and a post-test indicated that both feedback types significantly influenced learners’ writing accuracy. However, analysis of the participants’ performances on the post-test demonstrated that metalinguistic group outperformed computer-mediated one. Thus, the effect of metalinguistic feedback was more than that of computer-mediated feedback. In addition, both of them were more influential than no-feedback instruction. The findings of the present study can be fruitful for syllabus designers and EFL teachers. پرونده مقاله