Nowadays English was an international language, it was widely used; it did not only have an educational purpose, but was gradually spread to other sectors, especially the economic one. On May 6, 2002, then Prime Minister Tun Dr. Mahathir announced that the government was willing to reintroduce English as the medium of instruction. And on May 11, 2002, then Education Minister Musa Mohamad established a bilingual system that included the use of English for teaching science and mathematics (Tan, 2005, p. 50). Before this announcement was made, the Education Art 1996 established the national legislation The language (Malay language) shall be the principal medium of instruction in all educational institutions of the National Education System, except national-type schools or any other institutions education exempted by the Minister from this subsection (2006, p. 23). Following the announcement, primary and secondary school students will study science and mathematics in English. This may create uncertainty for students about using English as a medium for learning science and mathematics. According to the Ministry of Education (nd), the main purpose of reintroducing English as the medium of instruction was to improve their skills and adaptation of the language. skills of students and teachers through mathematics and science. Furthermore, this will help and encourage students to develop their language skills to a higher level. Doing so will help students perform optimally in and out of the classroom. This is because most of the information in scientific knowledge was written in English. Zahih Zakaria and Mohd Sallehhudin Abd Aziz (2011) stated: “This change in policy was deemed necessary to ensure that...... half of the paper......ik dan Pendidikan, Jil. 23, 142. Retrieved from http://web.usm.my/education/publication/MATHS%20AND%20SCIENCE%20IN%20ENGLISH_abstract.pdf Tan, P. K. W. (2005). The debate on the medium of instruction. - English as a Malay language? Language Issues and Language Planning, 50. Retrieved from http://www.factworld.info/malaysia/news/debate.pdfTan, Y.S. (2007). STUDENTS' ATTITUDES AND PERFORMANCE ORIENTATIONS TOWARDS LEARNING SCIENCE AND MATHEMATICS IN ENGLISH. Kajian Malaysia, Jld. XXV, No. 1, 23. Retrieved from http://web.usm.my/km/25(1)2007/KM%20ART%2025(1)_2.pdfZahih Zakaria and Mohd Sallehhudin Abd Aziz. (January 2011). Assessing student achievement: The second language factor (English language). The International Journal of Educational and Psychological Assessment, Vol. 6, 43. Retrieved from http://tijepa.books.officelive.com/Documents/A4V6.2_TIJEPA.pdf