Based on the survey responses of over 1000 attendees of growing and 1000 attendees of declining Mainline Protestant churches in Canada, this research examines patterns of denominational switching and the characteristics of switchers from both groups. Based on previous Canadian research we hypothesized, among other predictions, that the majority of our Mainline Protestant congregants would never have switched denominations and, of those who had, a plurality would indicate that their previous church was part of another Mainline Protestant denomination. These hypotheses were supported when the responses of growing and declining church attendees were combined but when the responses of the growing church congregants were tabulated separately they were not supported. We show how the switching patterns of the growing Mainline Protestant church congregants are more akin to those of Canadian Conservative Protestant church congregants and we offer explanations as to why this may be the case.