This study investigated students’ level of anxiety in academic writing. In addition, the author also found out about the causes of anxiety felt by students. Two instruments were used to answer two research questions. First, the using of Second Language Writing Anxiety Inventory (SLWAI) from Cheng (2004) which aimed to measure the level of student anxiety in academic writing. Then, the interview was conducted as a follow-up to find out the causes of anxiety felt by students. There were 71 students of 8th semester majoring in English Education at the Universitas Muhammadiyah Purwokerto as the respondents and they were asked to fill outa questionnaire. Furthermore, 9 out of 71 students were chosen to be interviewed based on high, averageand low anxiety level. The result obtained in this study showed that 8th semester students had average level of anxiety. While the causes of their anxiety were problem finding resources, language difficulties and fear of teacher evaluation, problems determining topics and lack of writing ability, as well as time pressure and confidence in writing.