Abstract Name : Nurhasanah Student No. : 0806102050095 Study Program : English Education Title : The Study on the Vocabulary Mastery of LP3I Students (A Descriptive Quantitative Research at LP3I Banda Aceh) Keywords : Vocabulary size test, memorizing strategy, vocabulary mastery This study was conducted with the aims to see the vocabulary mastery level and the memorization strategy that used by the students at LP3I Banda Aceh. The students were selected by random sampling technique with the consideration of the LP3I policy that requires all its students to memorize 500 words as the requirement to take midterm/final examination. The data was collected and analyzed in the form of qualitative approach.The instruments used in this study were test and questionnaire. The tests are adopted from Nation (2007), there is a 14.000 version containing 140 multiple choice items with 10 items from each 1000 words family level. Then the questionnaire consists of four questions of sub strategies of vocabulary learning adopted from Oxford (1990) cited in Azadeh (2009), and the choices are limited into yes and no. The result of the study revealed that the majority of students at LP3I are in the mid frequency level. Some of them are even in high frequency level and none of the students’ vocabulary is indicated low frequency level. Furthermore, in memorizing the vocabulary most of students did the three memorization strategies as suggested by Oxford (1990), which are grouping the words, making acronym and using imagery.