The present study investigates the effect of e-mail on Iranian learners of English and focuses on teaching thewriting skillvia e-mail. More specifically, the study investigates (a) whether using e-mail has any statistically significant effect on improving high school students' writing skill, and (b) whether the proficiency level has any relation with students’ writing improvement through using e-mail.To this end, 150 high school Iranian students were selected randomly and divided into 3 proficiency levels, namely high, mid, and low, based on their performances on an Oxford Placement Test (OPT). The participants at every proficiency level were divided into 3 subgroups to receive 3 methods of instruction, namely traditional face-to-face, through using e-mail, and through both the traditional method and using e-mail. After 3 months of instruction, a posttest was administered and the results were submitted to ANOVA. The results obtained revealed that using e-mail had a statistically significant effect on improving students' writing skills. The Scheffe post hoc results showed that the group with the e-mail treatment performed almost the same as the other 2 groups at the high proficiency level; in other words, the group at the high level did not benefit much from using e-mail; however, thelow and intermediate proficiency level participants did benefit from it. The findings are finally discussed with regard to how email can be exploited as an educational aid by teachers and learners.
