The study is designed to investigate the way pre-service English teachers use interaction modification in their teacher talk. Interaction modification is the way language teachers modify their teacher talk to communicate successfully with their students in the classroom and to help them understand and learn the target language better. Thirty two pre-service teachers participated in microteaching and their teacher talk was recorded and transcribed. Seven types of interaction modification were identified in their teacher talk; among them, repetitions and comprehension checks were the most frequently used. Their interaction modification varied according to their English proficiency, their foreign language teaching anxiety (FLTA), and lesson types. Proficient pre-service teachers tended to focus on reciprocal understanding between themselves and their students; less proficient ones tended to focus on their own understanding. The teachers with higher FLTA showed the tendency to avoid active interaction modification strategies compared to the ones with less FLTA. In PPP lessons, repetitions were predominantly frequently used. Comprehension checks were very often used in role-play and information gap lessons, and clarification requests in role-plays and language experience approach lessons. In the conclusion, some suggestions for pre-service teacher training courses to develop their teacher talk were made based on the findings.