Developing students' attitudes toward science is an important issue because societies need individuals who can contribute to scientific and technological developments. That's why using various and different instructional tools in science education may have an impact on students' attitudes towards science positively. Within this respect, the goal of the study is to investigate the effects of serious games on primary school students' (fifth-grade) science achievement related to the topic of light and sound, and attitudes towards science. A quasiexperimental research design was used in the study. Fifth-grade students from two different classes were the participants in the current study. The data was gathered by the science achievement test and the attitude scale. The findings revealed that whereas students in the experimental group, who were taught by serious games, developed their attitudes towards science significantly positive, their counterparts did not. There was no significant effect of serious game on students? achievement. This result showed that serious games as a different instructional tool may have crucial impacts on primary students' attitudes toward science.