Abstract: The present study was carried out in order to find out about the effect of two instructional programs, namely cooperative and individualistic instruction on the vocabulary and pronunciation improvement of low-intermediate EFL learners. The subjects were 50 students at the fifth grade of Mellal school aged 10-12 in Esfahan in Iran, who were randomly assigned to the experimental and control groups. The two selected groups were instructed over a period of ten weeks. For this purpose, a pretest-posttest experimental design was used. Prior to the treatment, a test for both vocabulary and pronunciation was developed, piloted, and administered to check the homogeneity of the participants. Then, the students’ scores in the homogeneity-check test were used as the pre-test score, too. For the treatment, the learners in the experimental group were instructed via cooperative technique whereas the learners in the control group received instruction according to a teacher-centered method following an individualistic-instructional approach. At the end of the study, the same test was administered to both groups as the post-test. Results suggested that both individualistic and cooperative instruction can enhance vocabulary achievement of Iranian low-intermediate EFL learners. However, no significant difference was found between the two groups regarding their vocabulary achievement. However, there was a significant difference between the two groups regarding their pronunciation achievement, and, thus, it was concluded that the application of collaborative methods in EFL classes can lead to an improvement in the learners’ pronunciation.