This meta-analysis was performed to determine the overall effectiveness of computer assisted instruction on students' academic achievement in science education from 2001 to 2007 in Turkey. The study reported the results of 65 effect sizes (ES) included in 52 studies. Grand mean for 65 ESs was found to be 1.12. This effect size can be interpreted as an average student's achievement moved from the 50th percentile to the 87th percentile in science learning when computer assisted instruction was used. In addition, two variables (grade level of subjects and instruction method of comparison group) had a statistically significant impact on the mean of ES. (Contains 1 figure and 2 tables.)