Fatemeh Takallou۱ - Assistant Professor in TEFL, Payame Noor University
Helena Safari - B.A. in TEFL , Payame Noor University
Maryam Haseli Beig - B.A. in TEFL , Payame Noor University

Several studies have been conducted so far, to investigate different errors EFL learners commit while writing English, because gaining mastery in writing skill has a significant role in promoting English proficiency in spite of its complexity .This research aims at examining the writings of high school students in grade nine to find their common writing errors as well as frequency and sources of committed errors. Participants chosen for this study were all grade nine students, both male and female, from ۴ different high schools in Karaj city- Alborz province and the instrument utilized to gather writing samples of participants was a test based on Prospect ۳ book consisting of different parts such as grammar, vocabulary and etc. After careful analyzing of data obtained from the tests, the results showed that grade ۹ students have some problems with grammatical, lexical and orthographical points in writing; among them, grammatical problems had the major role in committing errors. Furthermore it was found that different sources are responsible for committing writing errors, including inter-lingual sources, intra-lingual sources and ambiguous ones. But intra-lingual sources were the most significant one among various error sources

error, error analysis, inter-lingual, intra-lingual