This study investigated the effect of direct vocabulary learning using Computer Assisted Language Learning (CALL) on vocabulary knowledge, reading comprehension, and speed of word recognition. It found that students who used Tutorial CALL to learn highly frequent vocabulary did learn a significantly larger number of words than those in a control group. They decreased their reaction time for frequent word recognition as compared to the control group and they exhibited significantly better reading comprehension than a control group. The students in the treatment group studied approximately 2,000 of the highly frequent words in English on the computer for 3 hr per week for 8 weeks whereas the students in the control group spent the same amount of time reading texts and doing reading comprehension exercises. Although both groups showed increases in vocabulary gain, and reading comprehension, and a decrease in reaction time for frequent word recognition, the treatment students showed significantly greater gains than the control students.