ABSTRACT.- Our objective was to compare performance and carcass characteristics of backgrounding steers grazing poor quality pasture, receiving energy or protein supplements during summer, and on subsequent finishing period. Sixty Hereford steers (14 months; 348+-3 kg body weight [BW]) were blocked by BW and randomly assigned to one of three treatments (n = 20 per treatment): control (non-supplemented) and supplemented at 0.8% BW with whole grain of corn (CS) or lupin bean (LS) (phase I; 77 days). Over the following 84 days, none of the steers had access to supplement (phase II). During phases I and II, steers grazed together endophyte-infected tall fescue. In the last phase (phase III; 176 days), and until slaughter, steers grazed lucerne and orchard grass and were supplemented at 0.8% BW with high-moisture sorghum grain. Data were evaluated as a complete block randomized design with three treatments. Intake of supplement in CS and LS groups was 1.9 and 2.4 kg DM/d, respectively. Steers supplemented with lupin showed an improvement in the supplement conversion efficiency (5.7:1 vs. 10.0:1). At the end of phase I, BW and average daily gain were different between groups (LS > CS > control). Final body weight in phase II was greater in supplemented steers than in control steers. At slaughter, supplemented groups had greater hot carcass weight than the control group. The advantage obtained by supplementing steers with lupin, compared with corn, was lost in the subsequent phases, as reflected by the absence of differences in carcass weight. Our data illustrate that in similar scenario, energy supplementation is adequate and there is not any extra benefit of adding protein by the use of lupins when considering cattle management and economic factors. © (2024), (Sociedade Brasileira de Zootecnia). All rights reserved.