The research was conducted in English department of Muhammadiyah University og Purwokerto. The object of the research was fourth semester students of English Department Class C as the experimental group and those of class D as the control group. I administered pre test to both groups to examine their initial competence. The experimental group was given the treatment by Inquiry Based Teaching while the control the control group was taught by employing conventional learning model lecturing and discussion. The design of the study was quasy experimental research. The data collection usedtest as the instrument to measure the students competence . It was found out the test was 4,482, it was then compared to t_tabel with significant level @ = 0,05. The t Value was higher than t-tabel (4,482>1,993), meaning that the implementation of Inquiry based Teaching could improve the students understanding about the concept of Instructional Media and the Implementation. It could be seen from the significant difference of post test of two groups. It can be concluded that the hypothesis stating that teaching Instructional Media using Inquiry Based Teaching is effectif was proven.
Keywords: Inquiry Based Teaching, instructional Media