The main purpose of this study was to know the students’ weaknesses and strengths in learning English. To achieve the objective of the study, the writer conducted a descriptive research. This research was held at SMAN 2 Demak in the academic year 2015/2016. The subject of the study was XI grade of IPA 3, there were 40 students.
The instrument used in this study was test, the writer used diagnostic test. There were three skills in the test, reading test, writing test, and speaking test. In reading test, the students were asked to answer multiple choice question. In writing test, the students were asked to make a paragraph. In speaking test, the students were asked to make a dialogue.
Based on the result of the diagnostic test, it could be concluded that the students’ weaknesses was in reading skill, and the students’ strengths was in reading skill.

Keywords: need analysis, diagnostic test, good teaching