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).The present research considered the significance effects of two important independent variables self-monitoring and peer-monitoring in writing activities on Iranian English as a Foreign Language (EFL) learners. In this research we were supposed to investigate self-monitoring & peer-monitoring effects on 173 male and female learners' writing activities whose age ranged from 16 to 27, and they had a composing description writing paragraph as pre & posttest 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, L. Dunlap, G. Dunlap, L. Koegel, & R. Koegel 1991). This research studied about self-monitoring and peer-monitoring procedures which had new effects on learners' written tasks.