The objective of this paper is to compare the Jigsaw III technique (of cooperative learning) with the instructional teacher-centered teaching method in six graders in terms of the effect of written expression on their academic success. The universe of the study consists of 71 sixth-grade students studying during 2009-2010 academic term in a primary school in the province of Erzurum. Two classes were randomly selected: one (n = 35) of which was the control group where teacher-centered teaching method was applied, the other being experimental group (n = 36) where the Jigsaw III technique was applied. In the study, one of the most common application, pretest/posttest with control group experimental design, was chosen. The data regarding the academic success of the groups were collected by means of the achievement test in Turkish course as pretest, posttest and retention test; the students' opinions about the group works were obtained through feedback form, group work opinionnaire, and data were analyzed through 11.5 SPSS program. The results of the statistical analysis of teaching a written expression course showed that the experimental group did significantly better than the control group in terms of academic success. In addition, it can be said that the students had positive impressions on the Jigsaw III technique.