The success of GM herbicide tolerant canola is demonstrated by its acceptance by the farm community in Canada. There have been continuing comments, however, including some from major customers, suggesting that GM canola has lower quality than conventional canola. Data drawn from both the Western Canada Canola/Rapeseed Co-operative Test data from 1998–2001 and from the Canadian Grain Commission's harvest surveys of canola from 1996–2001 were used to compare the quality of GM and conventional canola registered and grown. Weed seed contamination of harvest survey samples decreased significantly as the herbicide tolerant lines increased in production. While variety registration data suggested GM and conventional lines had no differences in oil content, data from harvest surveys suggested that GM lines tended to have slightly higher oil contents. Protein and oil contents remain inversely related with no differences in the inverse relationship due to GM. While registration requires that all lines have less than 12 micromoles per gram of glucosinolates, data from harvest surveys show GM lines to have significantly less glucosinolates than conventional lines, possibly due to decreased contamination with cruciferous weeds. A comparison of glucosinolate contents between non-GM herbicide tolerant canola and conventional non-herbicide tolerant canola showed similar differences. There were no significant differences in chlorophyll content, erucic acid levels or saturated fatty acids but harvest survey data showed GM lines were slightly more unsaturated than conventional lines. It would seem safe to conclude that differences in quality between GM and conventional canola are due to the functioning of the GM trait – herbicide tolerance – that allows the GM canola to perform to its potential in the field.