Sustained silent reading (SSR) is usually defined as a students’ silent reading activity conducted in the fixed period of time in class. The main purpose of this study was to investigate the effect of SSR which was applied in TOEIC instruction in the college classroom to see the effect on the students' reading speed and reading comprehension. For one semester, the control group class consisted of traditional TOEIC practices, and the students of the experimental group, besides their regular TOEIC practices, read texts (about 500 words on average) from various English reading materials for 15 to 20 minutes on their own every class for one semester and filled in the activity sheets on which they marked the level of text interest and difficulty. The students' English reading comprehension and reading speed was measured twice, at the beginning and the end of the semester. The data showed that SSR class showed more improvement in terms of reading comprehension than the control class, but not in reading speed. However, the students of the SSR class answered more items in post reading comprehension test than the students of the control class. As for the students' responses to the texts’ interest and difficulty, it seemed that the easier the text was, the more interested the students were. The text difficulty, which was measured by the readability index that calculates text difficulty, was similar compared with the difficulty perceived by the students.