Based on a comprehensive literature review of ESP needs analyses, it is clear that an improvement in ability to read and understand academic papers should be one of the primary goals of any ESP course for university students majoring in science and technology. Although this implies the study of academic papers, some research conducted by questionnaire in Japan indicates that many teachers regard scientific texts written for the lay person to be the most appropriate material to achieve this goal. The purpose of this paper is to determine the most frequently used words in texts from academic scientific journals and to compare them with those used in texts from scientific magazines for the general public. The result of this research will show how different or how similar the two word lists are. Finally, the paper introduces a method of preparing a suitable word list for ESP students.