Abstract :
This research was a descriptive qualitative research. This research was done because there was the government regulation which sets international standard school program up in Indonesia. This judgment is caused many criticisms from many aspects. Concerning the school profile, the educator and student competence is required the consideration in constructing the program. Especially for the teachers who do not teach English subject matter. They have to use English instruction as a medium in teaching their subjects. Based on that problem, the researcher
did a research on how the use of English in teaching non English subject matter at the second grade of SMAN 1 Krian Sidoarjo. At the same time, the researcher analyzed whether the English language instruction is reasonable to be implemented or not.This research was taken in SMAN 1 Krian Sidoarjo, one of a pilot project of international standard school in Sidoarjo. The subject was the students of XI science 4. The class consisted of 39 students, 10 male and 29 female students. The researcher did this research in descriptive qualitative which was aimed to describe the implementation of using English as an instruction for teaching non English subject matter, it was in the form of descriptive qualitative. The data were collected by observation, interview and questionnaire. Then they were analyzed by using Milles and Huberman model which provides three steps, data reduction, data display and conclusion drawing or verification.