In this project, researchers investigate how mathematics faculty learn to teach mathematics courses using inquiry-based learning approaches. The researchers are following a group of instructors new to the methods over a period of two years and are documenting their learning process. Anecdotal information suggest that instructors' initial concerns refer to aspects such as where do they stand in the room or how much time to wait before answering a question. As they gain more experience their concerns shift towards understanding students' thinking. This knowledge will be useful for designing faculty development programs focused on specific challenges of learning to teach using inquiry-based learning approaches.