PURPOSE This study was done to develop a Web Based Instruction (WBI) program on safety for sixth grade elementary school students and to test its effectiveness. METHOD The web site is http://www.safeschool.co.kr. The effects were tested from Mar 24, to Apr 30, 2003. The participants were 150 students. Data were analyzed using descriptive statistics, and chi square-test, t-test, and repeated measure ANOVA. RESULTS For knowledge of safety precautions, the preliminary test had a mean score of 17.8, the immediate post-test, 20.9 and the 4 week post-test, 20.9. There were statistically significant differences among the three time points. For attitude to safety precautions, the preliminary test mean was 75.1, the immediate post-test, 80.8 and the 4 week post-test, 80.4. For motivation to learn safety precautions, the scores were significantly higher for the WBI group. Knowledge, attitude and motivation for accident prevention in the WBI group lasted longer than in the group with textbook-based instruction. CONCLUSION A WBI program should be used in each class to provide more effective safety instruction.