Evaluation is basically a matching process, which concerns matching learners' needs to available solutions. Through analysis and assessment of ESP textbooks, a much more promising and desirable approach to a theory of ESP takes place. To this aim, the purpose of the present study was to evaluate the ESP medical textbook. To gather the necessary data, two researcher-made questionnaires and one interview protocol were used. Medical instructors and learners answered to a 30-item questionnaire to express their attitudes towards different aspects of their ESP textbook. Besides, some members of both groups participated in the interviews to gain in-depth information about the study. They were both male and female. The findings revealed that instructors and learners had positive attitudes towards the content part of their ESP textbook. In addition, the findings revealed that there is a significant difference between the instructors' and learners' attitudes concerning the ESP textbook. The results of this study have a number of implications for medical instructors, learners, and syllabus designers.