Yes. There are strict quotas on the number of IMGs accepted into residency positions each year and these quota vary by province. Most Canadian medical schools have positions designated for IMG applicants in the first iteration; however, there is no guarantee that all available positions will be filled. In Quebec, there is a rigorous screening process for IMGs, and both IMGs and Canadian medical graduates (CMGs) compete for the same training positions.
In the second iteration, most vacancies become competitive. That is, both IMGs and CMGs compete for the same available positions, except for Ontario, Manitoba and Alberta. Ontario, Manitoba and Alberta programs will keep both IMG and CMG streams separate in second iteration, as it is in first iteration. Once again, there are no guarantees that all available positions will be filled.
Information about IMG quotas, if available, can be found in program descriptions.