Information on pollen-mediated gene flow (PMGF) in canola is useful for managing trait purity in commercial production. A multi-year, multi-site study was conducted to determine the frequency and distance of PMGF in commercial-scale fields of canola using the glyphosate tolerance trait as a marker. PMGF from glyphosate tolerant canola (source) to conventional canola (recipient) was measured over four years, 1999, 2000, 2001, and 2002, in 60 different field sites in Alberta, Manitoba, and Saskatchewan. Each field site consisted of glyphosate tolerant canola being produced adjacent to conventional canola. Transects parallel to the border between the source and recipient fields were established in the recipient field at distances of 10, 20, 50, 200, and 400 m from the border. A total of 1000 seedpods (siliques) were collected along each transect. Sixteen sub-samples of canola seed from each transect were analyzed for glyphosate tolerance by germinating the seeds in a glyphosate-containing media. Low levels of PMGF from glyphosate tolerant canola to conventional canola were detected at all sites. PMGF levels along the 10 m transect averaged 0.99, 0.75, 1.2, and 1.49% in 1999, 2000, 2001, and 2002, respectively. PMGF levels decreased exponentially with greater distance from the source field and, at 400 m, averaged 0.21, 0.14, 0.11, and 0.20% each year. These results from commercial-scale production fields are consistent with published information for canola.