A meta-analysis was performed to synthesize existing research comparing the effects of computer applications (i.e., computer-assisted instruction, computer simulations, and Web-based learning) versus traditional instruction on elementary school students' achievement in Taiwan. Forty-eight studies were located from four sources, and their quantitative data were transformed into Effect Size (ES). The overall grand mean of the study-weighted ES for all 48 studies was 0.449. The results suggest that computer application instruction is more effective than traditional instruction for elementary school students in Taiwan. However, none of the 14 individual variables, conjectured to be related to achievement, had a statistically significant impact on the mean ES.