Science content integration, or the simultaneous teaching of science with other subjects during learning activities, has been explored by multiple studies. However, due to a lack of consensus on its definition, it was difficult for educators in a local school district to discuss and evaluate the effectiveness of this instructional technique. This qualitative collective case study, based on a constructivist theoretical foundation, centered on the questions of how teachers defined and used science content integration, and perceptions of impediments to its use. Participants were five teachers in a suburban elementary school. The sources of data for this study were interviews, audio recordings of lessons, and teacher documents in the form of lesson plans. Data analysis was conducted through multiple coding procedures, allowing the emergence of themes. Data analysis showed that participants' beliefs and practices differed according to age levels and developmental needs of their students. Implications for positive social change include building from this study to provide content integration-based professional development, common planning time, and suitable materials to improve teachers' capacity to integrate science content into instruction. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]