Are grades determinant in the selection process?

Yes and no. McGill University requires that all applicants have a minimum Cumulative Grade Point Average of 3.0 for their undergraduate studies, or at least of 3.2 for the last two years of those studies. (This translates into a Second Class Upper Division in the British system.) Applicants who earned their Bachelor’s degree a long time ago and do not meet this standard, but who have since shown excellence in other ways, may still apply if they have since then completed a year of full-time studies in gradable courses (not pass/fail) at the undergraduate or graduate level. The required minimum CGPA for this extra course-work is 3.2. Again, all else being equal, a candidate with higher grades will be preferred over one with lower grades. But grades are only one of several factors that are taken into account.  more