In this paper, we report on teachers' use of curricula and other instructional resources to address Common Core State Standards (CCSS), as well as how use of instructional materials is related to instructional practice. We draw on data from the American Teacher Panel, a nationally representative sample of teachers who periodically provide perspectives on implementation of major education policies in classrooms and schools. Preliminary findings suggest that teachers are relying mainly on district- and teacher-developed materials to help students meet CCSS. Teachers also indicated using a range of online educational resources to support their instruction. This data will provide a preliminary picture about how CCSS is changing instructional materials and teaching in K-12 classrooms.