Research Findings: This article focuses on preschool science, an important but under-researched school readiness domain. There is considerable activity surrounding quality science in early childhood classroom practices, including state standards, curricula with science activities, and an extensive literature on potential best practices. However, there is very little empirical research focused on the effectiveness of these practices. The present article presents preliminary investigative research, a necessary first step in pursuing a research area that has been under explored. The first study uses a large, ethnically diverse statewide database of Head Start children's school readiness to show that children end their pre-kindergarten year with science readiness scores significantly lower than readiness scores in all other measured domains. The second study identifies low self-efficacy in science and time-management issues as two possible barriers for why preschool teachers may have difficulty teaching science. The third study reports on a program designed to integrate other readiness domains around science activities, with promising results for children's school readiness in multiple domains. Practice or Policy: The article concludes with a discussion of future directions, emphasizing the need to focus on science in preschool classrooms and the critical role that science education can potentially play in improving early childhood classroom practices and child outcomes. (Contains 4 tables.)