Because of being a developed country which is a phenomenon among the countries in the world, this desire inevitably has contributed the scientific and technological developments in educational areas as well. The expectation of these scientific and technological changes reflections in teaching areas to form permanent learning has developed the use technology in education. The use of computer in educational areas increases in our country together with the developed countries. Computer assisted instruction is mostly used in academic studies that investigate the success of difference and it is known to use control and experimental groups in these experimental studies. Meta-analysis summarizes the results of various studies in the fields of science and aims at reaching common judgment by combining the conclusions. The purpose of this study is to obtain a general opinion about effectiveness of taught courses which are carried out by using Computer-Assisted Instruction in Science and Mathematics in our country by using meta-analysis method. That is, meta-analysis method was used to combine the similar studies and to determine the mean effect of the Computer Assisted Instruction (CAI). The most important result of this study is that the Computer Assisted Instruction has an important level of superiority.