This study aimed to see if Computer-Assisted Language Learning is effective in improving learners’ vocabulary learning. For this purpose, 70 English students from a language institute in Khodaafarin, Iran, were chosen. To ensure the homogeneity of the participants, the Oxford Quick Placement Test (2004) was administered to all the participants and 60 students who were proven to be in pre-intermediate level were selected for the study and were assigned into two groups of 30. Then, the vocabulary knowledge scale was administered as a measure of pre-exposure to the target items. According to the results of the VKS, 50 words from the book Interchange 2 which were proven to be unfamiliar to the participants were selected. In the treatment, the experimental group used a computer, a projector, and a board; they had a few minutes to look at the vocabularies within the passages while having simultaneous access to the computers. But in the control group, the students were given neither the opportunity to use CALL in the classroom nor the chance to play the CD at home. After the treatment phase, the same teacher-made vocabulary test was administered as the post test of the learners’ vocabulary learning. The results of the post-test indicated that this method could positively influence the vocabulary learning of the participants in the experimental group. The overall findings of independent sample t-test and paired sample t-tests could reject the null hypothesis of this study predicting no effect for CALL instruction on the vocabulary learning of Iranian EFL students. تفاصيل المقالة