Abstract: Using computer programs has recently caused language teaching and learning to undergo influential changes. Computer proved to be an instrument for those who are willing to learn a foreign language. It should be pointed out that CALL programs certainly have helped to educators to develop different types of learning which is based upon these technologies. Computer-Assisted Language Learning (CALL) is among those programs, which has caused this great change. The present study had a quasi-experimental design and involved quantitative data collection procedures. Participants were males and were selected from second grade students of a guidance school in Guilan. The purpose of the present research was to investigate the effect of CALL on improving beginner EFLs' grammar learning. To this aim, a multiple-choice test of grammar namely KET, of which the reliability was 0.79, was administered to 127 EFL beginners out of whom sixty-four of the students were selected as homogeneous and randomly divided into two groups of thirty-two participants. Assigned groups were the control group that were taught with traditional grammar learning methods and an experimental group who underwent the CALL instruction. The results of the study through a posttest revealed that the experimental group outperformed the control group. Therefore, CALL appeared to be useful in developing English grammar of the EFL students. The researcher concluded that integrating technology to curriculum is beneficial for beginners and that the application of computer and its related technologies can facilitate grammar learning both inside and outside the classroom.