Abstract: This study aims to provide a linguistic taxonomy of frequent errors in Persian to English translation. It also proposes the most frequent and the least frequent errors among EFL students. Translation of Persian to English makes Iranian translators confront the problems such as Orthographic errors, Phonological errors, Lexico-Semantic errors and /or Syntactico-Morphological errors. The main concern of this study would be on the Syntactico-Morphological errors. Error Analysis is a procedure used by both researchers and teachers which involves collecting samples of learner language, identifying the errors in the sample, describing these errors, classifying them according to their nature and causes, and evaluating their seriousness. The researchers conducted a translation project on 500 EFL undergraduate university students in Teaching English as a Foreign Language, Translating and English Language and Literature field of studies. Students were asked to translation 30 sentences from Persian to English. After that, the researchers tried to rank and categorize them according to Contrastive Analysis and Error Analysis. At the content and context levels, there may be several shared properties between SL and TL equivalents which are connotatively motivated while at the formal level the lexical differences can be problematic. The researchers hypothesize that in errors in use of tenses and in use of articles are the most frequent errors. On the other hand, errors the use of plural morpheme are the least ones. The research is going to help to pinpoint the potential problematic errors and provide some pedagogical guidelines for teachers, syllabus designers and test constructors.