Vocabulary plays a part and parcel role in mastery of language. Therefore, the research focused on enabling students to memorize a wide range of vocabulary by using bilingual flashcards in ESP seminars. Quantitative and qualitative research methods were used in the research. Researchers worked on analyzing the results of inbound & outbound tests and 5 mini-tests with a comparison of previous semester data. Moreover, a questionnaire related to the feedback of vocabulary flashcards covered over 100 sophomore students. The efficiency of bilingual flashcards reveals an increase of almost 20% and 5.8% for the mini tests and inbound/ outbound tests respectively. It is worth emphasizing the questionnaire result showed that the majority of students gave weight to the efficiency of flashcards because they have no experience using vocabulary flash cards for their English classroom. Students tend to prefer to use flashcards individually out of class with the collaboration of classmates.