This paper investigates the English proficiency progress of first-year students of Nagasaki University by comparing their G-TELP scores in the first and second semesters of 2011. The data of the 1470 first-year students show that the improvements in mean test scores from the first semester to the second were statistically significant. Specifically, the students in the Faculties of Medicine and Pharmacology demonstrated the greatest improvement in the listening section, while students in the Faculties of Engineering and Fisheries showed the greatest improvement in the grammar and reading sections. This paper also examines the effectiveness of proficiency-based classes for the 485 second-year students of Economics, Engineering and Fisheries. Students' 2011 second-semester G-TELP scores were used to divide students into advanced, intermediate and lower-level classes. Subsequently, a post-test conducted in the first semester of 2012 demonstrated that proficiency-based classes were most effective for the lower-level students. The students in the advanced classes did not show any major improvements.