Most part of teaching and learning process in the classroom is done through interaction. The interaction between the teacher and students in the classroom interaction becomes one of important aspects to achieve the goal of learning. In the classroom, pre-teaching process can ease the students to learn deeper about the material. Activating background knowledge is one of strategies in pre-teaching. The research used a qualitative design with the subjects of the teacher and the students from three classes of Junior High School Widodaren 1, Ngawi. It had some purposes: 1) to analyze the structures of conversation between the teacher and the students during the phase of activating background knowledge, 2) to analyze how the teacher activates the students’ background knowledge, and 3) to determine the dominant type of talk used by the teacher during the phase of activating background knowledge. To collect the data, the researcher used observation, interview, and video recording. This study used Conversation Analysis (CA), where the conversation between the teacher and students during the phase of activating background knowledge was recorded and transcribed to find out the structures of conversation. To analyze the way the teacher activated the students’ background knowledge, the FLINT system was used. The findings of this research showed that the structures of conversation between the teacher and the students during the phase of activating background knowledge were turn-taking, adjacency pairs, and preference organization. The turn taking patterns between the teacher and the students were TàSSàTàSàTàSàTàSàTàSàTàSàTàSS. The type of adjacency pairs were question-expected answer and command-compliance. The preference organization was preferred of expected answer and compliance. The teacher activated the students’ background knowledge by asking questions, giving directions, repeating student’s response verbatim, praising or encouraging, and giving information. The dominant type of talk used by the teacher was asking question.