The present study highly supported the effective role of providing background information via email by the teacher to write e-mail by the students in learners' writing ability. A total number of 50 EFL advanced male students aged between 25 and 40 at different branches of Iran Language Institute in Tehran, Tehran. Through the placement test of Oxford English Language Placement Test (OELPT) the students' proficiency level seems to be nearly the same. Participants were randomly assign into two groups of experimental and control, each consisting of 25 students. After the administration of the proficiency test, all groups were assigned to write topic 1 as the pre-test. Next, the teacher involved the learners in the new instruction (treatment). During writing topics 2, 3, 4, 5, 6, and 7 experimental group's background knowledge was activated through e-mail before writing and e-mailing topics while the control group received no background knowledge activation through e-mail. After the treatment was given to the experimental group, the students in both groups were required to write another composition about the last topic, topic 8. Again, in this phase, none of the groups received any background information. The results indicated that providing background information via e-mail by the teacher to write email by the students significantly improved learners' writing ability.