In the present experimental study, the effects of cooperative learning method supported by mutliple intelligence theory (CLMI) on elementary school third grade students’ achievement on mathematics were investigated. The study, which had lasted nine consecutive weeks, was conducted at a public elementary school in thedistrict of Seyhan-Adana, Turkey in 2004-2005 academic year. The participants of the study were 85 students. For the purpose of this study, on experimental group cooperative learning method supported by mutliple intelligence theory (CLMI) was used as the method of instruction whereas the control groups were instructured utilizing the traditional teacher oriented method. “Mathematics Achievement Test (MAT)”, “Teele Inventory of Multiple Intelligences (TIMI)” and “Personal Information Form (PIF)” were used as the measurement instruments of the study. MAT was administered as pretest and posttest to the experimental and control groups. Furthermore, prior to the study TIMI and PIF (for getting personal information about students) were administered to all the participants. They also were used in order to constitute the cooperative learning teams in the experimental group. In this research, the data obtained by achivement test was analysed by using statistical techniques of covariance analysis.As a result, there was a statistically significant difference among experimental group and second control group in favor of the experimental group in the achivement test. Moreover, no statically significant differences were observed among the experimental group and the observed – directed group (first control group).