This study aimed to explore the impact of an introductory English course provided by the English Language Centre as a part of the Unified Scientific Track Program (USTP) at Taibah University, Saudi Arabia on developing the English language proficiency levels of students upon joining scientific colleges at three consecutive academic years, namely, 2015-2016, 2016-2017, and 2017-2018 at all the university campuses. The study compared the preplacement test scores to the post test scores showing the development occurred during a two-semester English course through the proficiency language levels of the Common European Framework of Reference (CEFR). The study revealed the positive impact of the introductory English language course to advance students' language proficiency level from A1 to B2. The study recommended the necessity of administering a standardised proficiency placement test (e.g. TOEFL, IELTS, Oxford, etc.) at the end of each school stage e.g. Intermediate & Secondary in order to make sure that students have achieved the target English language proficiency level