Multimedia has a critical role in learning and learning development in students. In this regard, current study is going to investigate the effect of researcher made multimedia on the high level of mentally retarded educable third grad students' learning in elementary students in Hamedan. Statistical society includes the whole male mentally retarded third grade students in the elementary schools in Hamedan. 28 people have been selected randomly among these retarded mentally educable students. Research method was Quasi-experimental using pre-post-test with control group. Experimental group has been taught by means of training researcher made media for two months. But, control group has been taught traditionally without using multimedia. Primarily, in order to investigate the expected changes, a pre-test has been conducted for both groups. After performing pre-test, experimental group was exposed to independent variable and then a post test was performed on both groups. After 9 weeks, the second post-test has been conducted to evaluate the level of retention. Data was analyzed in descriptive level with mean and standard deviation and in inferential level with statistical analysis covariance. Findings showed that experimental group had progressed significantly by use of researcher made multimedia compare with control group. According to findings, it can be concluded that teaching and learning by means of multimedia will be much more effective for educable students.
