The aim of this study is to determine the effect of sustainable environmental activities aimed at preschool children on raising environmental awareness. The research was conducted at Baglarbasi Kindergarten in the Haliliye district of Sanliurfa Province, Turkey. A total of 101 children aged 4-5 years participated in the study. Sustainable environmental activities developed by the researchers were applied to the experimental group, while activities specified in the 2013 Preschool Education Program by the Turkish Ministry of National Education (MoE) were applied to the control group. In order to determine the students' level of environmental awareness, an "Environmental Awareness Test" was created, and its validity and reliability studies were conducted. The Environmental Awareness Test was administered to the study group as a pre-test and post-test. Analysis of the obtained parameters showed that the application of science activities in the experimental group significantly increased the children's level of environmental awareness and was higher compared to the control group. Furthermore, this difference was found to have a significant effect size. The results indicate that sustainable environmental activities are more effective than the activities in the MoE program in fostering environmental awareness and/or sensitivity in preschool children.