The total number of words among the three sets of vocabulary was 9,108, while their overlap consisted of 1,798 words. Out of these 1,798 words, 535 words do not appear in JSH textbook vocabulary. Assuredly, then, these 535 words may be considered as being the most important words needing to be acquired for an adequate comprehension of Business English, considered from the standpoint of authentic business communications, educational business texts, and tests for measuring communication skills. Excluding JSH vocabulary, the most frequently appearing 100 business-oriented words common to the three business-oriented vocabularies are attached in the Appendix.