This study evaluated the translation quality of English equivalents of Persian proper nouns in the tourist signs and bilingual boards in Isfahan. To find different errors in the translations of the bilingual boards and tourist signs, the data were collected directly by taking picture or writing exactly from the available tourist signs and bilingual boards. Then, the errors were assessed by Multilingual eLearning in Language Engineerin (MeLLANGE) translation error typology, a model for evaluating and marking the errors of a project by Leonardo da Vinci center of education and culture in the University of Paris. The findings revealed that the most frequent errors in Persian-English translation were related to errors of incorrect cases in full upper cases, errors of transferring the content by source language intrusion in the un-translated translatable cases and errors related to the syntax of language. As a conclusion, using expert and knowledgeable translators, applying a consistent method, and employing a comprehensive and standard system can be effective to reduce such errors.
