In this research the effects of educational digital games and in-class educational games on scientific process skills of 6 years old children were investigated. The research was carried out with 70 preschool children who were educated in a primary school in Turkey. In the research, quasi-experimental design was used. Within the scope of the research, there are 3 groups including 2 experimental and 1 control groups. The educational digital games with the children in the Experiment I group were performed with in-class educational games with the children in the Experiment II group. The research covered a 10-week period. In order to test the hypotheses of the research, t test for the related samples, Wilcoxon Signed Sequence test, single factor ANOVA analysis for unrelated samples, Kruskal Wallis H-Test and Man Whitney U-Test were performed. According to the analysis results of the scientific process skill test scores of the groups after the application, it was found that there was no significant difference between experiment I and experiment II. It was determined that there was a significant difference between the experiment I and experiment II groups and the control group, and this difference was in favor of the experimental groups.