Assessment is a strategy the teachers use to evaluate, measure, and document the students' academic readiness and learning progress. Indonesian government holds a national assessment through Ujian Nasional or National
Examination. Since 2014, Computer-based National Examination had been implemented in some schools in Indonesia, but there were some pros and contras towards its implementation. This study was conducted to explore how students, teachers, and administrators prepared themselves before the administration of Computer-based National Examination, the problems they faced during the administration of Computer-based National Examination, and how they solved the problems. In addition, the study also investigated their perception towards the implementation of Computer-based National Examination. The research method used in this study is qualitative descriptive case study research involving the 9th grade students of Junior High School, the 9th grade teachers, and the administrators (proctors, invigilators and school manager) of the computer-Based National Examination. There were 17 students of 9th grade ( out of the 288), four teachers, three proctors and three invigilators in charge of the execution of National Examination Academic Year
2018/2019. The school manager participant was the Vice Headmaster of Curriculum. The data were obtained through interview and open-ended questionnaire. The results of the study showed that the students as well as the school have made a good academic preparation before the administration of Computer-based National Examination. They found some problems during the administration of the examination, but they could solve and overcome them. All respondents, the students, the teachers, and the administrators perceived positively towards the implementation of the computer-based National Examination due to its advantages; namely: practicality, simplicity, efficiency, economy, as well as higher test items security and higher students' integrity.