This paper is a brief survey of the pedagogic issues and literature in the field of vocabulary in English for Specific Purposes (ESP). There is agreement among ESP practitioners that the teaching of vocabulary needs to be improved if second language learners are to cope adequately with academic writing in a specialist discipline such as medicine. The problem still remains, however, as to the nature of the vocabulary that should be taught. The paper reviews some of the work which has been done by researchers who have attempted to answer this question by categorizing and quantifying the vocabulary of scientific texts.