Writing is an important experience through which we are able to share ideas, arouse feelings, persuade and convince other people (white & Arndt, 1991). It is important to view writing not solely as the product of an individual, but as a cognitive, social and cultural act. Writing is an act that takes place within a context, that accomplishes a particular purpose and that is appropriately shaped for its intended audience (Hamplyones & Condon, 1989). Here, the present research considers the significance effects of two important independent variables self-monitoring and peer-monitoring in writing activities on Iranian EFL learners. In this research it was supposed to study new effects of two Meta cognitive strategies self-monitoring and peer-monitoring on 173 male and female learners' writing activities whose age ranged between the age 16-27, and they had a composing description writing paragraph as pre & post test in the same conditions. Although many studies have been conducted on the effects of self-monitoring with a variety of students across a variety of settings (Amato-Zech, Hoff, & Doepke, 2006 Cooper et al., 2007, Dunlap, Dunlap, Koegel, & Koegel 1991). But goal of this study was to increase the participant's on-task behavior in self & peer-monitoring (E. Johnson, 2007, Self &Peer-monitoring added). Although both of them were useful for providing challengeable students, and became useful for prosocial life, but self-monitoring helped them to become awareness of their weaknesses and strengths to increase positive way of the quality and quantity of their learning in written task, and peer-monitoring occurred when the students achieved recognition level to evaluate the other peers' behavior, and it was obviously understood that it needed more training time to arrive at the level of recognition of each other's behavior.