In the present study, an attempt has been made to determine the demotives affecting EFL learning of Iranian Islamic seminary students and also to distinguish the motivated and demotivated EFL learners in terms of their EFL learning as the major focus of this study. Fifty Iranian EFL seminary students were investigated using two validated questionnaires. First a modified version of The Attitude/Motivation Test Battery Questionnaire (AMTB) originally developed by Gardner (2004) was used to determine the degree of learners' motivation. Second a modified version of Warrington's (2005) questionnaire was administered to determine the demotivating factors from the students' point of view. Then, the IOPT (Interchange Objective Placement Test) was administered to measure the general proficiency of the subjects under study. The comparison of the IOPT score means of the two groups revealed a significant difference in the results of IOPT of students with higher scores in the AMTB and those with lower scores. That is, the more motivated the students were, the higher their IOPT scores were. Furthermore, factors such as the improper method of English teaching, frequency of classes in a week, problems in understanding listening materials and lack of use of English in students' real life were found to be the essential demotivating factors among Iranian seminary students. Having known the barriers of learning, the teachers and Islamic Propagation Office materials developers can organize their activities so that they would lead to better understanding of the lessons and improvement of teaching programs.