摘要:In the framework of language teaching, the writing skill requires to be encouraged during the language learners’ course of study. Since metadiscourse markers help transform a tortuous piece of text into a coherent and reader-friendly one, knowledge about the metadiscourse, amongst other things, is used to improve writing skill. The current study aimed to investigate the influence of instruction of metadiscourse markers on intermediate EFL learners’ writing performance by using metadiscoursal taxonomies proposed by Hyland (2005). For this purpose, a pet test was administrated to 60 intermediate students in Iran Language Institute in Urmia. Having being homogenized by Preliminary English Test (PET), they were assigned randomly into two groups. Both the control and the experimental group sat for a pretest of writing test in the form of a cloze test which aimed to measure the learners’ initial knowledge of writing performance. The experimental group was exposed to explicit instruction of metadiscourse markers for seven successive sessions. On the other hand, the control group didn’t receive any instruction. Eventually, a post test designed to evaluate their writing ability with the focus of metadiscourse markers was administered to both groups. The findings implied generally that the implementation of metadiscourse markers (via instruction) significantly improves EFL learners’ writing ability.