Interviews and surveys are widely used in social science research in general and in legislative studies in particular. As research methods, they help us understand the thoughts and intentions of parliamentarians, making them one of the most valuable sources of data for the study of political behavior. Interviews and surveys may be personally administered as in interviews or self-administered as in questionnaires. Despite their importance, however, the current practice of conducting interviews typically lacks quality control whereas surveys generate low response rates and tend to suffer from selection bias. This chapterfocuses on the use of interviews and surveys in legislative research. It describes some of the most influential works based on interview research, as well as the greatest challenges involved in their use. It then explains how interviews with parliamentarians are conducted and concludes by offering relevant practical advice and presenting tools for addressing the challenges of interviews and surveys in future legislative research.