Nair, J., Penner, G. B., Yu, P., Lardner, H. A., McAllister, T., Damiran, D. and McKinnon, J. J. 2015. Evaluation of canola meal derived from Brassica juncea and Brassica napus seed as an energy source for feedlot steers. Can. J. Anim. Sci. 95: 599-607. This study evaluated the substitution of barley grain with two sources of canola meal (CM) derived from Brassica napus and B. juncea on performance of feedlot cattle. Crossbred steers [n=300; initial body weight (BW)=311±23 kg] were allotted to 25 pens with each pen randomly assigned to one of five treatments. The control backgrounding diet consisted of 39% barley silage, 30.4% barley grain, 22.8% brome hay and 7.8% supplement, while the control finishing diet consisted of 88.3% barley grain, 4.4% barley silage and 7.3% supplement (dry matter basis). The control diets contained no CM during backgrounding and finishing. Treatment diets included 15 and 30% B. napus or B. juncea meal during backgrounding and 10 and 20% during finishing, with canola meal replacing barley grain in both phases. In each phase the data were analyzed as a 2×2 factorial plus a control. Cattle fed CM substituted diets during backgrounding had greater (P<0.05) dry matter intake (DMI), average daily gain (ADG) and final BW relative to those fed the control diet. Gain to feed ratio (G:F) and calculated net energy for maintenance (NE_m) and gain (NE_g) were not affected (P>0.05) by treatment. During finishing, DMI and ADG did not differ (P>0.05) across treatments. Feed efficiency, NE_m and NE_g decreased (P<0.05) at the 20% CM level relative to 10%. Over the entire feeding period, G:F, NE_m and NE_g were reduced (P<0.05) with higher inclusion of CM in the diet. The percentage of cattle grading Canada AAA was reduced (P<0.05) by CM. These results indicate that regardless of type CM has a lower net energy value than barley grain and that it is not an equivalent energy substitute for cereal grains over the entire feeding period.