Teaching English vocabulary presents many problems because of its vast size and constant enrichment and expansion. According to various sources there may be about three million words in the English language, about eight hundred thousand words registered in English dictionaries and some thirty thousand words in daily use of an English speaker. How many English words should there be in the mind of our students to make them proficient users of the English language? The problem seems to have been solved by the introduction of core vocabulary concept whose main objective is to limit the number of words for teaching, focusing attention on the most frequent, most useful, most productive words in meaning, word derivation and collocability. Approximately, three thousand words may constitute core vocabulary of an English student. Core vocabulary should also take into account special vocabulary to meet the professional needs of students and their interests. For example, a graduate student vocabulary at foreign languages faculty includes linguistic and literary terminology, conversational clichés and mass media words and expressions.Lists of recommended vocabulary should be the result of lexical research and be a part of lexical syllabus, a guide for teachers and students. What should we teach students first: words or vocabulary learning strategies? The number of approximately three thousand words may hardly guarantee high level proficiency, thus students must be taught vocabulary learning strategies to be able to upgrade their vocabulary on their own. The study of Modern English Lexicology lays the theoretical foundation for the formation of vocabulary learning strategies and they must be further consolidated in the classes of practical English. It is important to promote the students’ abilities to cope with new and unfamiliar vocabulary items and to refine their abilities to make intelligent guesses. The best friend of students remains a Dictionary and students should be well equipped with different types of English dictionaries and spend much time on reading the information provided in them, developing skills in their use. The knowledge of available reference books and dictionaries is crucial to training professionals.Linguistic research should begin with dictionaries and result in the improvement of lexical syllabus. At present, there appeared new computer-based sources, indicating frequency, range and coverage of English words but in our teaching practice we still rely on our intuition and the vocabulary provided by English coursebooks in current use. How can we update and upgrade our vocabulary? No matter what kind of English coursebook is used, as a rule, it fails to meet all teachers’ requirements and tastes of every student. Vocabulary of any coursebook should be upgraded depending on the aims of the course and its users. Picking up typical collocations and idioms from mass media helps students to upgrade their English and international culture and provides observations on contemporary vocabulary use. Listening to BBC radio and television is a real test for our students’ knowledge of English vocabulary. Research on new words and new tendencies in vocabulary development must be undertaken both by teachers and students. What techniques succeed best with students? In the light of learner-centered approach the most effective activities are those where the students are in the center of input, storage, and retrieval of active vocabulary. Among the most fruitful activities there are mini-speeches, interviews, snowball stories, tests for friends, crosswords, word webs and vocabulary projects. They are designed and performed by the students themselves with the view of recycling active vocabulary.Teaching English vocabulary to foreign students should be based on similarities and differences between English and their mother tongue. Lexical syllabus must identify the so-called false friends of a translator and plan the activities to deal with them. Theory, practice and research into vocabulary should go hand in hand with creating a.friendly environment for studying English.