The consistent prevalence of computer science in our society and the urgent need for STEM professionals in the U.S. raised the need for computer science education at the K-8 level. Researchers have examined the challenges, possible approaches, and contents of teaching computer science. However, there has been limited research on teachers' conceptualization and practice of teaching computer science in their classes at the K-8 level. This study aimed to examine K-8 teachers' conceptions and practices of teaching computer science in Indiana. To this end, the research question focused on how K-8 teachers conceptualize computer science and how K-8 teachers practice teaching computer science. This study utilized an explanatory sequential mixed method embedded with a multiple case design to answer the research questions. From kindergarten to eighth grade, nine teachers who had computer science teaching experience participated in this study. The data collected from the participants included questionnaires, semi-structured interviews, class observation, and teaching materials. Thematic analysis procedure and constant comparative analysis procedure were employed as the data analysis approaches. The results showed that the participants of this study used computers and technology indistinguishably. In addition, the participants viewed computer literacy and digital citizenship as the essential parts of computer science. However, the participants' teaching practice emphasized coding and computer literacy more than digital citizenship, which was not alien to their concepts of computer science. The participants of this study have taught computer science as separate activities as opposed to a sustained curriculum. Moreover, the participants of this study relied on free and ready-to-use teaching materials, especially those that included hands-on activities. The participants of this study agreed that computer science should be a separate class and taught by specialists, even though they all have plenty of computer science teaching experience and have valued integrating computer science with other subject areas. Furthermore, the participants of this study integrated computer science with other subject areas without being aware. The participants of this study discussed the influential factors that impact computer science teaching: (1) computer science curriculum resources, (2) time to learn computer science, (3) priority of computer science in teaching, and (4) professional development on computer science. It is recommended that clarification on what computer science is and how to teach the computer science concepts need to be delivered to K-8 teachers. More accessible and ready-to-use computer science curricula are needed, especially the curricula that include hands-on computer science activities and integrate computer science with other subject areas. Based on the results of this study, I suggest facilitating K-8 teachers' computer science teaching by enhancing teachers' computer science knowledge and competence and integrating computer science with other subject areas. More longitudinal studies capturing teachers' conceptions and practices of teaching computer science will need to be conducted in the future. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]