Defining “IS habit” as the extent to which using a particular IS has become automatic in response to certain situations, we developed a reliable and validated scale to measure the construct. The final scale was tested in the context of a theoretical model developed based on recent work on IS continuance. The central idea of this model is to consider habit as a moderator of the relationship between intention and continuous IS usage. The paper describes the scale development process and presents the resulting 6-item measurement instrument. Furthermore, it reports on the results of using the scale to test the “moderator-hypothesis”.