The present study focuses on the assessment of vocabulary potential of teacher-created pedagogical materials to use in the class of English for Specific Purposes (ESP) taught to Russian undergraduates, majoring in Chemical Engineering, in a large public technical university. Specifically, the aim of the research is to examine the vocabulary distribution in the collection of course materials in terms of its range, frequency and variety. The motivation behind the study is that ESP instructors often have to rely on their own intuition during the text selection and material development due to the fact that there is the lack of pedagogical materials covering discipline-specific vocabulary of every specialization. ESP instructors teach English first, integrating the presentation of topics from subject matter classes and the major challenge consists in the lack of content-based knowledge of ESP instructors to select the domain vocabulary to L2 learners. Thus, to facilitate customized language acquisition (basic engineering, academic and specialized vocabulary) and to determine the extent to which the vocabulary contained in the texts is specialized and relevant to L2 learners' domain, corpus software "Range" is used to run the analysis. The results suggest that the ESP corpus promotes the acquisition of high frequency English words (the first and the second 1,000), basic engineering and academic vocabulary. The results also demonstrate insufficient level of teacher-created materials for specialized vocabulary development and highlight the need to include texts of varying vocabulary types, and to optimize specialized wordlist.