This contribution deals with the research methodology and results of one phase of design-based research (hereinafter referred to as DBR) of an ESP coursebook – evaluation of the coursebook by means of a questionnaire survey. The ESP coursebook was designed for the course English for Information Technology taught at Brno University of Technology in the Czech Republic. The main objective of DBR is to establish a link between the design of the coursebook and its iterative testing for the purpose of its evaluation and re-design so that it would be the most appropriate teaching and learning tool for the target group of students. Besides the optimisation of the coursebook quality by means of the production of substantive design principles (characteristics of the coursebook design itself) and procedural design principles (characteristics of the coursebook design approach), the research results should lead to the verification and development of the existing theories of the ESP learning materials development. The first part of this contribution focuses on research methodology, the coursebook and samples characteristics and development of a research tool. The second part provides data analysis and interpretation. Besides the recommendations concerning the coursebook redesign, the research findings reveal similarities and differences in teachers’ and students’ opinions about the ESP coursebook quality.